2x+8y=57 and 3x+5y=78SOLVE THIS QUESTION!!!

2x+8y=57 and 3x+5y=78SOLVE THIS QUESTION!!!

2x + 8y = 57 |x3| 6x + 24y = 171
3x + 5y = 78 |x2| 6x + 10y = 156 -
14y = 15
y = $frac{15}{14}$

Substitusi nilai y tersebut ke salah satu persamaan:
3x + 5y = 78
3x + 5( $frac{15}{14}$ ) = 78
3x + $frac{75}{14}$ = 78 (kedua ruas dikali 14)
42x + 75 = 1092
42x = 1092 – 75
42x = 1017
x = $frac{1017}{42} = frac{339}{14}$