Solve the following simultaneous equations:

Question

Solve the following simultaneous equations

a) 5x+3y=7

7x-y=13

b) 4x+5y=8

5x+4y=12

(I need only b)

Answer 1

5x + 3y = 7

7x - y = 13

Plan: solve for y in second equation, then substitute for y in 1st equation to determine x. Substitute value for x in second equation to determine y.

4x + 5y = 8

5x + 4y = 12

Plan: multiply top equation by 5 and bottom equation by 4. subtract 2nd equation from 1st (will eliminate x term) and solve for y, then plug value back into 1st equation to solve for x.