All categories

3 years ago

Sharon tried to solve an equation step by step.

Mathematics

2 answers:

ASHA 777 [7]3 years ago

8 0

Answer:

Sharon made a mistake in step 2.

Step-by-step explanation:

Sharon tried to solve an equation step by step.

$\qquad\begin{aligned} 9&=-3(e-2)\\\\ \\ 9&=-3e+6&\green{\text{Step } 1}\\\\ \\ 15&=3e&\blue{\text{Step } 2}\\\\ \\ 5&=e&\purple{\text{Step } 3}\\\\ \end{aligned}$

The correct steps are:

The given equation is

$9=-3(e-2)$

Step 1: Using distributive property we get

$9=-3e-3(-2)$

$9=-3e+6$

Step 2: Subtract 6 from both sides.

$9-6=-3e+6-6$

$3=-3e$

Step 3: Divide both sides by -3.

$\frac{3}{-3}=\frac{-3e}{-3}$

$-1=e$

Therefore, Sharon made a mistake in step 2.

Pavel [41]3 years ago

4 0

Answer:

Step 2

Step-by-step explanation:

Khan academy inequalities 7th grade math unit test

You might be interested in

Starting from 300 feet away, a car drives toward you. It then passes by you at a speed of 48 feet per second.The distance d (in

Sergio [31]

About 2 seconds away from you

4 0

3 years ago

What is the answer?<br> A.<br> B.<br> C.<br> D.

mina [271]

Answer:

something

Step-by-step explanation:

5 0

3 years ago

Can someone please help me with these 7 questions please?

yarga [219]

$(1)\ (-xy)^3(xz)$

Expand

$(-xy)^3(xz) = (-x)^3* y^3*(xz)$

$(-xy)^3(xz) = -x^3* y^3*xz$

Rewrite as:

$(-xy)^3(xz) = -x^3*x* y^3*z$

Apply law of indices

$(-xy)^3(xz) = -x^4y^3z$

$(2)\ (\frac{1}{3}mn^{-4})^2$

Expand

$(\frac{1}{3}mn^{-4})^2 =(\frac{1}{3})^2m^2n^{-4*2}$

$(\frac{1}{3}mn^{-4})^2 =\frac{1}{9}m^2n^{-8$

$(3)\ (\frac{1}{5x^4})^{-2}$

Apply negative power rule of indices

$(\frac{1}{5x^4})^{-2}= (5x^4)^2$

Expand

$(\frac{1}{5x^4})^{-2}= 5^2x^{4*2}$

$(\frac{1}{5x^4})^{-2}= 25x^{8$

$(4)\ -x(2x^2 - 4x) - 6x^2$

Expand

$-x(2x^2 - 4x) - 6x^2 = -2x^3 + 4x^2 - 6x^2$

Evaluate like terms

$-x(2x^2 - 4x) - 6x^2 = -2x^3 -2x^2$

Factor out x^2

$-x(2x^2 - 4x) - 6x^2 = (-2x-2)x^2$

Factor out -2

$-x(2x^2 - 4x) - 6x^2 = -2(x+1)x^2$

$(5)\ \sqrt{\frac{4y}{3y^2}}$

Divide by y

$\sqrt{\frac{4y}{3y^2}} = \sqrt{\frac{4}{3y}}$

Split

$\sqrt{\frac{4y}{3y^2}} = \frac{\sqrt{4}}{\sqrt{3y}}$

$\sqrt{\frac{4y}{3y^2}} = \frac{2}{\sqrt{3y}}$

Rationalize

$\sqrt{\frac{4y}{3y^2}} = \frac{2}{\sqrt{3y}} * \frac{\sqrt{3y}}{\sqrt{3y}}$

$\sqrt{\frac{4y}{3y^2}} = \frac{2\sqrt{3y}}{3y}$

$(6)\ \frac{8}{3 + \sqrt 3}$

Rationalize

$\frac{8}{3 + \sqrt 3} = \frac{3 - \sqrt 3}{3 - \sqrt 3}$

$\frac{8}{3 + \sqrt 3} = \frac{8(3 - \sqrt 3)}{(3 + \sqrt 3)(3 - \sqrt 3)}$

Apply different of two squares to the denominator

$\frac{8}{3 + \sqrt 3} = \frac{8(3 - \sqrt 3)}{3^2 - (\sqrt 3)^2}$

$\frac{8}{3 + \sqrt 3} = \frac{8(3 - \sqrt 3)}{9 - 3}$

$\frac{8}{3 + \sqrt 3} = \frac{8(3 - \sqrt 3)}{6}$

Simplify

$\frac{8}{3 + \sqrt 3} = \frac{4(3 - \sqrt 3)}{3}$

$(7)\ \sqrt{40} - \sqrt{10} + \sqrt{90}$

Expand

$\sqrt{40} - \sqrt{10} + \sqrt{90} =\sqrt{4*10} - \sqrt{10} + \sqrt{9*10}$

Split

$\sqrt{40} - \sqrt{10} + \sqrt{90} =\sqrt{4}*\sqrt{10} - \sqrt{10} + \sqrt{9}*\sqrt{10}$

Evaluate all roots

$\sqrt{40} - \sqrt{10} + \sqrt{90} =2*\sqrt{10} - \sqrt{10} + 3*\sqrt{10}$

$\sqrt{40} - \sqrt{10} + \sqrt{90} =2\sqrt{10} - \sqrt{10} + 3\sqrt{10}$

$\sqrt{40} - \sqrt{10} + \sqrt{90} =4\sqrt{10}$

$(8)\ \frac{r^2 + r - 6}{r^2 + 4r -12}$

Expand

$\frac{r^2 + r - 6}{r^2 + 4r -12}=\frac{r^2 + 3r-2r - 6}{r^2 + 6r-2r -12}$

Factorize each

$\frac{r^2 + r - 6}{r^2 + 4r -12}=\frac{r(r + 3)-2(r + 3)}{r(r + 6)-2(r +6)}$

Factor out (r+3) in the numerator and (r + 6) in the denominator

$\frac{r^2 + r - 6}{r^2 + 4r -12}=\frac{(r -2)(r + 3)}{(r - 2)(r +6)}$

Cancel out r - 2

$\frac{r^2 + r - 6}{r^2 + 4r -12}=\frac{r + 3}{r +6}$

$(9)\ \frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14}$

Cancel out x

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4x + 8}{x} \cdot \frac{1}{x^2 - 5x - 14}$

Expand the numerator of the 2nd fraction

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4x + 8}{x} \cdot \frac{1}{x^2 - 7x+2x - 14}$

Factorize

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4x + 8}{x} \cdot \frac{1}{x(x - 7)+2(x - 7)}$

Factor out x - 7

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4x + 8}{x} \cdot \frac{1}{(x + 2)(x - 7)}$

Factor out 4 from 4x + 8

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4(x + 2)}{x} \cdot \frac{1}{(x + 2)(x - 7)}$

Cancel out x + 2

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4}{x} \cdot \frac{1}{(x - 7)}$

$\frac{4x + 8}{x^2} \cdot \frac{x}{x^2 - 5x - 14} = \frac{4}{x(x - 7)}$

$(10)\ (3x^3 + 15x^2 -21x) \div 3x$

Factorize

$(3x^3 + 15x^2 -21x) \div 3x = 3x(x^2 + 5x -7) \div 3x$

Cancel out 3x

$(3x^3 + 15x^2 -21x) \div 3x = x^2 + 5x -7$

$(11)\ \frac{m}{6m + 6} - \frac{1}{m+1}$

Take LCM

$\frac{m}{6m + 6} - \frac{1}{m+1} = \frac{m(m + 1) - 1(6m + 6)}{(6m + 6)(m + 1)}$

Expand

$\frac{m}{6m + 6} - \frac{1}{m+1} = \frac{m^2 + m- 6m - 6}{(6m + 6)(m + 1)}$

$\frac{m}{6m + 6} - \frac{1}{m+1} = \frac{m^2 - 5m - 6}{(6m + 6)(m + 1)}$

$(12)\ \frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}}$

Rewrite as:

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{1}{y - 3} \div \frac{2}{y^2 - 9}$

Express as multiplication

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{1}{y - 3} * \frac{y^2 - 9}{2}$

Express y^2 - 9 as y^2 - 3^2

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{1}{y - 3} * \frac{y^2 - 3^2}{2}$

Express as difference of two squares

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{1}{y - 3} * \frac{(y - 3)(y+3)}{2}$

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{1}{1} * \frac{(y+3)}{2}$

$\frac{\frac{1}{y - 3}}{\frac{2}{y^2 - 9}} = \frac{y+3}{2}$

Read more at:

brainly.com/question/4372544

3 0

2 years ago

6. Romeo is planning to elope with Juliet tonight. He knows that her windowsill is 18 feet from the ground. He also knows the 4-

Ierofanga [76]

Answer:

24' ladder

Step-by-step explanation:

It is sometimes useful to illustrate situations given in problems, as in this case;

The wall will be a vertical with a height 18 ft and the ladder will be away from the wall at the bottom and against the wall at the top end;

This is shown in the picture and as can be seen, it is a right-angle triangle;

We are told there is 4-to-1 rule, with which we can find the distance of the ladder from the wall at the bottom, denoted as a in the picture;

The rule is essentially saying the ratio of the vertical height of the ladder to the horizontal distance is 4 : 1, or ⁴/₁ (or just 4)

We know the vertical height of the ladder needs to be 18 ft since the window is that high up the wall;

The ratio will be 18 : a, or ¹⁸/ₐ

We can set the fractions equal to each other and solve:

¹⁸/ₐ = ⁴/₁

¹⁸/ₐ = 4

18 = 4a

a = 18/4

a = 4.5

The distance from the wall at the bottom should be 4.5 ft according to the 4-to-1 rule

Now we have the 2 sides of our triangles we can use Pythagoras theorem to find the length of the ladder, denoted x;

x² = (18)² + (4.5)²

x² = 324 + 20.25

x² = 344.25

x = 18.5539753

The ladder must be at least 18.6' long to be able to lean against the wall, reaching the window and complying with the 4-to-1 rule;

The ladder size therefore will be the 24' ladder, since it has a maximum length of 21' which can reach the window;

The smaller option, the 20', could be used since the reach is 19' 10", which is sufficient to reach Juliet but it would not likely be suitable for climbing into the window since it is not long enough;

Since he may climb into the window according to the scenario, the answer should be the 24' ladder both if he does or does not climb into the window;

I'm quite clueless about what to do with the information in the last 2 columns, not even sure what they mean to be honest so I think they are irrelevant.

4 0

3 years ago

I was literally thanking brainly but they took it down lma{}, i take it back

gizmo_the_mogwai [7]

Took what back lol....

3 0

3 years ago

Read 2 more answers