Question

What is the value of the y variable in the solution to the following system of equations?
5x + 3y = 7
3x - 5y = -23

A)-1

B)1

C)-4

D)4

Answer 1

do you have a guess?

Answer 2

i would say B

Answer 3

how did you get that answer?

Answer 4

i guessed

Answer 5

We want to eliminate x so what we are going to do enlarge to equations to same number to do so we employ 3 and 5

Answer 6

multiply by 3 the first equations
you got 15x + 9y =21

Answer 7

and second one by -5 you got
-15x +25y = 115

Answer 8

finally you add to equations and voila