How do you solve the system of equations 9x - 2y = 25 and 4x - 5y = 7?

Aug 6, 2018

color(maroon)(x = 3, y = 1

Explanation:

$9 x - 2 y = 25$ Eqn (1)

$4 x - 5 y = 7$ Eqn (2)

36x - 8y - (36x - 45y) = 100 - 63, color(red)(" Eqn (1) * 4 - Eqn (2) * 9 "

$- 8 y + 45 y = 37$

$37 y = 37 \text{ or } y = 1$

Substituting value of y in Eqn (1),

$9 x - 2 \cdot 1 = 25$

$9 x = 25 + 2 = 27$

$9 x = 27 \text{ or } x = \frac{27}{9} = 3$