Question

2x+3y-17=0 3x+7y-12=0 solve by cross multiplication

Answer 1

2x+3y-17=0

3x+7y-12=0

2x+3y=17

3x+7y=12

We know pattern of cross multiplication

b1 c1 a1 b1

× × ×

b2 c2 a2 b2

3 17 2 3

×. × ×

7 12 3 7

$a \div b1 \times c2 - b2 \times c1$

=

$b \div c1 \times a2 - c2 \times a1$

=

$- 1 \div a1 \times \: \: b2 - b1 \times a2$

a÷36-119 = b÷51-24 = -1 ÷ 21 - 9

a÷ -83 = b÷27 = -1÷12

a÷ -83=-1÷12 b÷27 = -1÷12

a = 6.91 b = 2.25