Question

Solve the system using elimination: 3x + 4y = 31 and 2x - 4y = -6
Please help. Thank you.

Answer 1

x =5, y = 4

Explanation:

3x + 4y = 31..... (1)

2x - 4y = -6..... (2)

Adding equations (1) & (2)

`3x + \cancel{4y} = 31 \\2x - \cancel{4y} = -6\\ - - - - - - - \\ 5x = 25 \\ x = (25)/(5) \\ \bold{ \purple{x = 5}} \\ plug \: x = 5 \: in \: eq \: (1) \\ 3(5) + 4y = 31 \\ 15 + 4y = 31 \\ 4y = 31 - 15 \\ 4y = 16 \\ y = (16)/(4) \\ \bold{ \red{y = 4}}`