Question

solve the following pair of linear equation by cross multiplication method : 4x +3y =28 ; 9x - 5y = 63​

Answer 1

x= 7    

y=0

Step-by-step explanation:

Given,

4x + 3y = 28

⇒4x + 3y -28=0...............(1)

9x - 5y = 63

⇒9x - 5y - 63=0................(2)

On comparing it with general equation

$a_1x + b_1y +  c_1$ = 0

$a_2x + b_2 + c_2$ = 0

x = (b₁c₂ - b₂c₁)/(a₁b₂ - a₂b₁)

y = (c₁a₂ - c₂a₁)/(a₁b₂ - a₂b₁)

x=$\frac{(9)(-63)-(-5)(-28)}{(4) (-5) - (9)(3)}$

x=$\frac{-189-140}{-47}$

x=$\frac{-329}{-47}$

x= 7

y=$\frac{(28)(9)- (63)(4)}{(4)(-5) - (9)(-5)}$

y=0