112,463 views
5 votes
5 votes
3. Solve -5x + 8y = 24 and 4x - 8y = -22 by elimination. Show your work.

User HeLomaN
by
3.3k points

1 Answer

18 votes
18 votes

Answer

x = -2 and y = 7/4

Step-by-step explanation:

Given the following system of equation

-5x + 8y = 24 --------------- equation 1

4x - 8y = -22 --------------- equation 2

Step 1: we need to eliminate y because the both equations has the same coefficient

To eliminate y, add equation 1 and 2 together

(-5x + 4x) + (8y - 8y) = 24 + (-22)

-x + 0 = 24 - 22

-x = 2

x = -2

To find y, put the value of x into equation 2

4x - 8y = -22

4(-2) - 8y = -22

-8 -8y = -22

Isolate 8y

-8y = -22 + 8

-8y = -14

Divide both sides by -8

-8y/-8 = -14/-8

y = 14/8

y = 7 / 4

Therefore, x = -2 and y = 7/4

User Lance Cleveland
by
3.0k points