Question

3x+2y=9 9x+4y=21 find it by substitution method

Answer 1

Given equations

$3x+2y=9$

$\implies 3x=9-2y$

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

$9x+4y=21$

$\implies 9(\dfrac{9-2y}{3})+4y=21$

$\implies 3(9-2y)+4y=21$

$\implies 27-6y+4y=21$

$\implies -2y=21-27$

$\implies -2y = -6$

$\implies y = \dfrac{-6}{-2}$

$\implies y= 3$

Substituting the value of y, we get,

$\implies x = \dfrac{9-6}{3}$

$\implies x = \dfrac{3}{3}$

$\implies x = 1$

$\boxed{\boxed{\bold{Therefore, \ the \ values \ of \ x \ and \ y \ are \ 1 \ and \ 3 \ respectively}}}}}}$

                                                       

Answer 2

Answer:

y = 3 and x = 1

Step-by-step explanation:

3x+2y=9

3x=9-2y

x=9-2y/3

substituting the above equation in the second eqn

9(9-2y/3)+4y = 21

27-2y=21

-2y=21-27

-2y=-6

y=3 and x=1