Question

x/3+y/4 =11 , 5x/6 - y/3 =-7
by substitute method ​

Answer 1

Answer:

$\frac{x}{3} + \frac{y}{4} = 11 \\ \frac{4x + 3y}{12} = 11 \\ 4x + 3y = 11 \times 12 \\ 4x + 3y = 132⟹ ⓵ \\ \\ \frac{5x}{6} - \frac{y}{3} = - 7 \\ \frac{15x - 6y}{18} = - 7 \\ 15x - 6y = - 7 \times 18 \\ 15x - 6y = - 126⟹ ⓶ \\ \\ (4x + 3y = 132) \times 2 \\ 8x + 6y = 264 ⟹⓵ \\ \\ 8x + 6y = 264\\ 15x - 6y = - 126 \\ - - - - - - - - - \\ 23x = 138 \\ x = \frac{138}{23} \\ \boxed{ \large x = \underline{ \underline{ \bf 6}}} \\ \\ 15x - 6y = - 126 \\ 15(6) - 6y = - 126 \\ 90 - 6y = - 126 \\ 90 + 126 = 6y \\ 216 = 6y \\ \frac{216}{6} = y \\ \boxed{ \large \underline{ \underline{ \bf 36}} = y}$