Find the solution of the system of equations.
3x+4y=-7
-3x=8y=-1

x = -5

y = 2

Step-by-step explanation:

3x + 4y = -7 eqn 1

-3x - 8y = -1 eqn 2

First, let's take eqn 1, to find the value of y

3x + 4y = -7

Make y the subject of the formula

4y = -7 - 3x

Divide both sides by 4, to get y

4y/4 = -7 - 3x / 4

y = (-7 - 3x) / 4

Substitute y into eqn 2

-3x - 8y = -1

-3x - 8(-7 - 3x) / 4 = -1

Open the bracket with -8

-3x + (56 + 24x )/ 4 = -1

LCM = 4

(-12x + 56 + 24x) / 4 = -1

(-12x + 24x + 56) / 4 = -1

(12x + 56)/4 = -1

Cross multiply

12x + 56 = -4

12x = -4 -56

12x = - 60

Divide both sides by 12 , the get the exact value of x.

12x/12 = -60/12

x = - 5

Insert the value of x = -5 into the equation 1

3x + 4y = -7

3(-5) + 4y = -7

-15 + 4y = -7

4y = -7 + 15

4y = 8

Divide both sides by 4

4y/ 4 = 8/4

y = 2

Hint, to confirm if the values are correct

Pick any of the two eqns

Let's pick eqn 2.

-3x - 8y = -7

x = -5

y = 2

-3(-5) - 8(2) =

= 15 - 16

= -1

So therefore, our values are correct

d

step-by-step explanation: