Question

solve 2x- 3y = 13 and 7x + 2y = 20 by subtitution method and hence find the value of m for which y = mx +7 ​

Answer 1

Answer:

1.

2x-3y=13

x=(13+3y)/2

2.

7x+2y=20

7((13+3y)/2)+2y=20

(91+21y)/2+2y=20

91+21y+4y=40

25y=-51

y=-51/25

x=[13+3(-51/25)]/2

=[13+(-153/25)]/2

=86/25

now....

-51/25=m(86/25)+7

(-51/25)-7=m(86/25)

-226/25=m(86/25)

m=-226/86