# How do you solve 8x-9y=32.5 and 7y-2x=-10.5 using substitution?

Sep 9, 2017

Solution: $x = 3.5 , y = - 0.5$

#### Explanation:

$8 x - 9 y = 32.5$(1) , $7 y - 2 x = - 10.5$(2) , From equation (2)

we get $2 x = 7 y + 10.5 \mathmr{and} x = 3.5 y + 5.25$ (3), Putting

$x = 3.5 y + 5.25$ in equation (1) we get,

$8 \left(3.5 y + 5.25\right) - 9 y = 32.5 \mathmr{and} 28 y + 42 - 9 y = 32.5$ or

$19 y = 32.5 - 42 \mathmr{and} 19 y = - 9.5 \mathmr{and} y = - 0.5$ Putting

$y = - 0.5$ in equation (3) we get, $x = 3.5 \cdot \left(- 0.5\right) + 5.25$ or

$x = 3.5 \therefore$ Solution: $x = 3.5 , y = - 0.5$ [Ans]