Question

Variable
Cross multiplication method?
3x+2y +25=
0
2x+y +10=0​

Answer 1

Answer:

3x+2y+25=0-------(1)

2x+y+10=0-------(2)

A1=3 ,B1=2 & C1=25

A2=2 ,B2=1 & C2=10

A1×B2 - A2×B1=3×1 - 2×2= 3 - 4= -1

So we can solve the simultaneous equations by using cross multiple rule :

X/B1×C2 - B2×C1 = Y/C1×A2 - C2×A1 = 1/A1×B2 - A2×B1

=>X/2×10-1×25 = Y/25×2-10×3 = 1/3×1 - 2×2

=>X/20-25 = Y/50-30 = 1/3-4

=>X/-5 = Y/20 = 1/-1

=>X/-5 = 1/-1 & Y/20 = 1/-1

=>X=5 & Y= -20

SO;(X , Y) = (5 , -20)

Hope it help you

Thanks