Question

Which of the following ordered pairs represents the solution to the system given below?

x − 4y = 7
5x + 9y = 6

Answer 1

It’s 3,-1

Explanation:

You have to plug in the points u can use a calculator or work it by hand but I did it on the calculator and that’s what I got

Answer 2

x − 4y = 7
5x + 9y = 6

5x − 20y = 35 //1st * 5
5x + 9y = 6

5x +9y - 5x + 20y = 6 - 35 //2nd - 1st
5x + 9y = 6

29y=-29
5x=6-9y

y=-1 //1st : 29
5x=6-9*(-1)

y=-1
x=15:5 //2nd : 5

y=-1
x=3

check:
for x=3 and y=-1 there is:
x − 4y = 7 is 3 − 4*(-1) = 7 is 7=7 ok
5x + 9y = 6 is 15-9=6 is 6=6 ok

answer: (3;-1) represents the solution.