226k views
0 votes
4x + 5y = 7 and 8x + 5y = 9 *
Elimination

User Cory Gross
by
4.6k points

2 Answers

4 votes
it should be y=2 after you eliminate
User Shrikant Mavlankar
by
4.8k points
3 votes

Answer:

Solve equation [2] for the variable y

[2] y = 8x + 7

// Plug this in for variable y in equation [1]

[1] 4x - 5•(8x+7) = -9

[1] -36x = 26

// Solve equation [1] for the variable x

[1] 36x = - 26

[1] x = - 13/18

// By now we know this much :

x = -13/18

y = 8x+7

// Use the x value to solve for y

y = 8(-13/18)+7 = 11/9

Solution :

{x,y} = {-13/18,11/9}

User Roman L
by
4.5k points