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2 years ago

77 decreased by twice of a number

1 answer:

nataly862011 [7]2 years ago

8 0

Use a variable for the unknown number so it would be 77-2x also if you don't know a number and a variable together means to multiply them

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Find x when y=6 in the literal equation 5x+4y=39

sergeinik [125]

The equation is like this 5×3 + 4×6 = 39
X = 3
Brainly would be awesome ❤️

5 0

2 years ago

The difference between the two roots of the equation 3x^2+10x+c=0 is 4 2/3 . Find the solutions for the equation.

andrezito [222]

Answer:

Given the equation: $3x^2+10x+c =0$

A quadratic equation is in the form: $ax^2+bx+c = 0$ where a, b ,c are the coefficient and a≠0 then the solution is given by :

$x_{1,2} = \frac{-b\pm \sqrt{b^2-4ac}}{2a}$ ......[1]

On comparing with given equation we get;

a =3 , b = 10

then, substitute these in equation [1] to solve for c;

$x_{1,2} = \frac{-10\pm \sqrt{10^2-4\cdot 3 \cdot c}}{2 \cdot 3}$

Simplify:

$x_{1,2} = \frac{-10\pm \sqrt{100- 12c}}{6}$

Also, it is given that the difference of two roots of the given equation is $4\frac{2}{3} = \frac{14}{3}$

i.e,

$x_1 -x_2 = \frac{14}{3}$

Here,

$x_1 = \frac{-10 + \sqrt{100- 12c}}{6}$ , ......[2]

$x_2= \frac{-10 - \sqrt{100- 12c}}{6}$ .....[3]

then;

$\frac{-10 + \sqrt{100- 12c}}{6} - (\frac{-10 + \sqrt{100- 12c}}{6}) = \frac{14}{3}$

simplify:

$\frac{2 \sqrt{100- 12c} }{6} = \frac{14}{3}$

$\sqrt{100- 12c} = 14$

Squaring both sides we get;

$100-12c = 196$

Subtract 100 from both sides, we get

$100-12c -100= 196-100$

Simplify:

-12c = -96

Divide both sides by -12 we get;

c = 8

Substitute the value of c in equation [2] and [3]; to solve $x_1 , x_2$

$x_1 = \frac{-10 + \sqrt{100- 12\cdot 8}}{6}$

$x_1 = \frac{-10 + \sqrt{100- 96}}{6}$ or

$x_1 = \frac{-10 + \sqrt{4}}{6}$

Simplify:

$x_1 = \frac{-4}{3}$

Now, to solve for $x_2$ ;

$x_2 = \frac{-10 - \sqrt{100- 12\cdot 8}}{6}$

$x_2 = \frac{-10 - \sqrt{100- 96}}{6}$ or

$x_2 = \frac{-10 - \sqrt{4}}{6}$

Simplify:

$x_2 = -2$

therefore, the solution for the given equation is: $-\frac{4}{3}$ and -2.

3 0

2 years ago

Factor 2x(squared)-9x-18?

Finger [1]

Here: =(2x+3)(x-6) =2x²-12x+3x-18 =2x²-9x-18 So the answer is (2x+3)(x-6)

7 0

2 years ago

Pizza-By-The-Slice sells 7 slices every 10 minutes on average. How many

Dvinal [7]

I think you’re answer is 42 slices of pizza.

the way i worked it out is by finding out how many minutes are in an hour (60 mins). after that i divided it by 10(mins), which would have gotten me 6. therefore i multiplied 7 x 6 which gave me 42.

3 0

2 years ago

Read 2 more answers

3.14=7x-2y

eimsori [14]

3.14=7x-2y

move 7x to the other side

sign changes from +7x to -7x

3.14-7x=7x-7x-2y

3.14-7x=-2y

Divide both sides by -2

3.14/-2-7x/-2=-2y/-2

3.14/-2=-1.57

-7x/-2=7x/2

Answer:

y=-1.57+7x/2

5 0

3 years ago