Question

Jordan wants to solve the following system using the elimination method:

2x + 3y = 10
x + y = 7

What number should the equation x + y = 7 be multiplied by to eliminate y?

Answer 1

see explanation

Explanation:

Given the 2 equations

2x + 3y = 10 → (1)

x + y = 7 → (2)

Multiplying (2) by - 3 and adding to (1) will eliminate y

- 3x - 3y = - 21 → (3)

Add (1) and (3) term by term to eliminate y, that is

- x = - 11 ( multiply both sides by - 1 )

x = 11

Substitute x = 11 into either of the 2 equations and evaluate for y

Substituting into (2)

11 + y = 7 ( subtract 11 from both sides )

y = - 4

Solution is (11, - 4 )