Ask question

Ask question

All categories

2 years ago

7

PLEASE HELP WITH GRADE 11 MATH. Make sure you show the formula. Substitute values and show all mathematicall operations! show yo

ur work. please!

1 answer:

Degger [83]2 years ago

5 0

3x+y

x

=−3

=−y+3

The second equation is solved for xxx, so we can substitute the expression -y+3−y+3minus, y, plus, 3 in for xxx in the first equation:

\begin{aligned} 3\blueD{x}+y &= -3\\\\ 3(\blueD{-y+3})+y&=-3\\\\ -3y+9+y&=-3\\\\ -2y&=-12\\\\ y&=6 \end{aligned}

3x+y

3(−y+3)+y

−3y+9+y

−2y

y

=−3

=−3

=−3

=−12

=6

Plugging this value back into one of our original equations, say x = -y +3x=−y+3x, equals, minus, y, plus, 3, we solve for the other variable:

\begin{aligned} x &= -\blueD{y} +3\\\\ x&=-(\blueD{6})+3\\\\ x&=-3 \end{aligned}

x

x

x

=−y+3

=−(6)+3

=−3

The solution to the system of equations is x=-3x=−3x, equals, minus, 3, y=6y=6y, equals, 6.

We can check our work by plugging these numbers back into the original equations. Let's try 3x+y = -33x+y=−33, x, plus, y, equals, minus, 3.

\begin{aligned} 3x+y &= -3\\\\ 3(-3)+6&\stackrel ?=-3\\\\ -9+6&\stackrel ?=-3\\\\ -3&=-3 \end{aligned}

3x+y

3(−3)+6

−9+6

−3

=−3

=

?

−3

=

?

−3

=−3

Yes, our solution checks out.

Example 2

We're asked to solve this system of equations:

\begin{aligned} 7x+10y &= 36\\\\ -2x+y&=9 \end{aligned}

7x+10y

−2x+y

=36

=9

In order to use the substitution method, we'll need to solve for either xxx or yyy in one of the equations. Let's solve for yyy in the second equation:

\begin{aligned} -2x+y&=9 \\\\ y&=2x+9 \end{aligned}

−2x+y

y

=9

=2x+9

Now we can substitute the expression 2x+92x+92, x, plus, 9 in for yyy in the first equation of our system:

\begin{aligned} 7x+10\blueD{y} &= 36\\\\ 7x+10\blueD{(2x+9)}&=36\\\\ 7x+20x+90&=36\\\\ 27x+90&=36\\\\ 3x+10&=4\\\\ 3x&=-6\\\\ x&=-2 \end{aligned}

7x+10y

7x+10(2x+9)

7x+20x+90

27x+90

3x+10

3x

x

=36

=36

=36

=36

=4

=−6

=−2

Plugging this value back into one of our original equations, say y=2x+9y=2x+9y, equals, 2, x, plus, 9, we solve for the other variable:

\begin{aligned} y&=2\blueD{x}+9\\\\ y&=2\blueD{(-2)}+9\\\\ y&=-4+9 \\\\ y&=5 \end{aligned}

y

y

y

y

=2x+9

=2(−2)+9

=−4+9

=5

The solution to the system of equations is x=-2x=−2x, equals, minus, 2, y=5y=5y, equals, 5.

You might be interested in

20 POINTS Congratulations, you just got a job! The company you are working for gave you a $50 signing bonus, and you are being p

olga_2 [115]

Answer:

its the one where the line starts at 50

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Expand (x-2) (x-1). Must be in polynomial form.

Ludmilka [50]

To expand two terms such as these, we can use the method called FOIL (stands for First, Outer, Inner, Last). Here is what I mean:

We have two terms: (x - 2)(x - 1)

We should first multiply the First two terms of each term in order to complete the F stage:

(x)*(x) = $x^{2}$

So then, we take the two outer terms and multiply them together to complete the O stage:

(x)*(-1) = -x

So far we have two things that we have calculated; at the end of the FOIL process we will have four.

To keep going with the FOIL, we now multiply the two inner terms to complete the I stage:

(-2)*(x) = -2x

Last but not least, we need to complete the L stage - so we multiply the two last terms of each term:

(-2)*(-1) = 2

Now that we have our four terms, let us add them together and combine like terms:

$x^{2} + (-x) + (-2x) + 2$

Since -x and -2x both have the x portion in common and they are added together, we can add them to create one single term:

-x + (-2x) = -3x

So now that we have our terms completed, we can combine into one polynomial equation:

$x^{2} + (-3x) + 2$ or $x^{2} -3x+2$

6 0

3 years ago

For her presentation on the Wonders of the World, Mary baked a square pyramid-shaped cake as pictured below. The slant height of

mihalych1998 [28]

Answer:

$V=196in^3$

Step-by-step explanation:

The volume of a pyramid is:

$V=\frac{A_{b}h}{3}$

where $A_{b}$ is the area of the base and $h$ is the height (the perpendicular measurement between base and highest point, not the slant height)

Since the base is a square, the area is given by:

$A_{b}=l^2$

where $l$ is the length of the side: $l=8in$ , thus:

$A_{b}=(8in)^2\\A_{b}=64in^2$

Now we need to find the height, for this we use the right triangle that forms with half of a square side (8in/2 = 4in), the slant height (10in), and the height.

In this right triangle, the slant height is the hypotenuse, the leg 1 is the unknown height, and leg 2 is half of the square side.

Using pythagoras:

$hypotenuse^2=leg1^2+leg2^2$

substituting our values, and indicating that leg 1 is height h:

$(10in)^2=h^2+(4in)^2$

$100in^2=h^2+16in^2$

and solving for the height:

$h^2=100in^2-16in^2\\h^2=84in^2\\h=\sqrt{84in^2}\\ h=9.165in$

and finally we calculate the volume using this height and the area of the base:

$V=\frac{A_{b}h}{3}$

$V=\frac{(64in^2)(9.165in)}{3} \\V=195.5in^3$

rounding to the nearest cubic inch: $V=196in^3$

4 0

3 years ago

What do we call the statement that determines if the null hypothesis is rejected?

geniusboy [140]

Answer:

c) alternate hypothesis

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

The line m has a slope of 2/3.Which line described below is the only line that could be parallel to line m?

ANEK [815]

Answer:

Parallel lines have the same slope, so the one with the same slope.

7 0

3 years ago