Question

0.4x-1.5y =6.5
0.3x+0.2=0.9

Answer 1

Given equations

$0.4x-1.5y=6.5$

$\implies \dfrac{4}{10}x - \dfrac{15}{10}y = \dfrac{65}{10}$

Multiplying throughout by 10, we get,

$\implies 4x-15y=65 --(1)$

$0.3x+0.2y=0.9$

$\implies \dfrac{3}{10} x + \dfrac{2}{10} y=\dfrac{9}{10}$

Multiplying throughout by 10, we get,

$\implies 3x+2y=9--(2)$

(1) * 3

(2) * 4

$12x-15y=195\\\underline{12x+8y=36}\\\underline{\underline{-23y=159}}}$

$\implies \boxed{\boxed{\bold{ y = \dfrac{-159}{23} }}}}}$

(1) * 2

(2) * 15

$8x-30y=130\\\underline{45x+30y=135}\\\underline{\underline{53x = 265}}$

$\implies \boxed{\boxed{\bold{x = 5}}}}}}$