Question

Solve simultaneous equation....4x-5y and 2x+y=4


`4x - 5y = 20and2x + y = 4`
how to solve simultaneous equation?​

Answer 1

(
`(20)/(7)`, -
`(12)/(7)` )

Explanation:

4x - 5y = 20 → (1)

2x + y = 4 → (2)

subtract 2x fro both sides in (2)

y = 4 - 2x → (3)

substitute y = 4 - 2x into (1)

4x - 5(4 - 2x) = 20 ( distribute parenthesis and simplify left side )

4x - 20 + 10x = 20

14x - 20 = 20 ( add 20 to both sides )

14x = 40 ( divide both sides by 14 )

x =
`(40)/(14)` =
`(20)/(7)`

substitute this value into (3)

y = 4 - 2(
`(20)/(7)` ) =
`(28)/(7)` -
`(40)/(7)` = -
`(12)/(7)`

solution is (
`(20)/(7)` , -
`(12)/(7)` )