Question

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

Answer 1

Answer:

( $\frac{20}{7}$, - $\frac{12}{7}$ )

Step-by-step 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 = $\frac{40}{14}$ = $\frac{20}{7}$

substitute this value into (3)

y = 4 - 2($\frac{20}{7}$ ) = $\frac{28}{7}$ - $\frac{40}{7}$ = - $\frac{12}{7}$

solution is ( $\frac{20}{7}$ , - $\frac{12}{7}$ )