Question

Solve the Solve the simultaneous equations 2x+3y=20 x+5y=31

Answer 1

`x = 1` and
`y = 6`

Explanation:

Given

`2x + 3y = 20`

`x + 5y = 31`

Required

Solve for x and y

Make x the subject in the second equation

`x = 31 - 5y`

Substitute 31 - 5y for x in
`2x + 3y = 20`

`2(31 - 5y) + 3y = 20`

`62 - 10y + 3y = 20`

`62 - 7y = 20`

Collect like terms

`-7y = 20 - 62`

`-7y = - 42`

Solve for y

`y = (-42)/(-7)`

`y = 6`

Substitute 6 for y in
`x = 31 - 5y`

`x = 31 - 5 * 6`

`x = 31 - 30`

`x = 1`