Question

Solve for x using

cross multiplication.
4x - 3
3 =
3
x+8
2
x = [?]

Answer 1

Given equation are 3x+4y=11 and 2x+3y=8

Comparing with a

1

x+b

1

y+c

1

=0 and a

2

x+b

2

y+c

2

=0 we have

a

1

=3,b

1

=4,c

1

=−11 and a

2

=2,b

2

=3,c

2

−8

Now , x=

a

1

b

2

−a

2

b

1

b

1

c

2

−b

2

c

1

and y=

a

1

b

2

−a

2

b

1

c

1

a

2

−c

2

a

1

⇒x=

3×3−2×4

4x(−8)−3×(−11)

and y=

3×3−2×4

−11×2−(−8)×3

⇒x=

9−8

−32+33

and y=

9−8

−22+24

⇒x=1 and y=2