Can someone explain the steps to answer this problem with the elimination method?

1. Multiply the first equation by 3,and multiply the second equation by -2.

3(5x+2y=15)

−2(3x+3y=9)

Becomes:

15x+6y=45

−6x−6y=−18

Add these equations to eliminate y:

9x=27

Then solve 9x=27for x:

9x /9 = 27 /9

(Divide both sides by 9)

x=3

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

5x+2y=15

Substitute3forxin5x+2y=15:

(5)(3)+2y=15

2y+15=15(Simplify both sides of the equation)

2y+15+−15=15+−15(Add -15 to both sides)

2y=0

2y /2 = 0 /2

(Divide both sides by 2)

y=0

2. Multiply the second equation by -1, then add the equations together.

(4x+2y=−7)

−1(4x−6y=−11)

Becomes:

4x+2y=−7

−4x+6y=11

Add these equations to eliminate x:

8y=4

Then solve 8y=4 for y:

8y /8 =4 /8

(Divide both sides by 8)

y=  1 /2

Now that we've found y let's plug it back in to solve for x.

Write down an original equation:

4x+2y=−7

Substitute

1 /2  for y in 4x+2y=−7:

4x+2( 1 /2 )=−7

4x+1=−7(Simplify both sides of the equation)

4x+1+−1=−7+−1(Add -1 to both sides)

4x=−8

4x /4 = −8 /4

(Divide both sides by 4)

x=−2

x=−2 and y=  1/2

the answer is b. 60. each interior angle in 120, so the exterior angle must be 60 in order to add up to 180

step-by-step explanation: