Question

2x-3y=13,
7x-2y=20
Using both substiTution and elimination

Answer 1

Answer:

By substitution method.

2x= 13+ 3y

x=13 +3y/2.............(1)

putting the value of x in eq. 2

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

91+21y/2 -2y = 20

91 + 21y - 4y

__________. = 20

2

91 + 17y /2 = 20

91 + 17y = 40

17y = 40- 91

17y = -51

y = -51/17

y = -3.............

putting the value of y in eq...(1)

x = 13 + 3 ( -3 )/2

x = 13 -9/2

x = 13 - 9

---------

2

x = 4/ 2

x = 2............

FOLLOW ME..

Answer 2

Answer:

2x-3y=13

7x -2y =20

by using elimination method

2x-3y=13×7

7x-2y=20×2

14x-21y=91

14x-4y=40

by cancellation of 14x in both terms

I) -17y=69

y=69÷-17= -4·05

2x-3(-4·05)=13

2x+12·15=13

2x=13-12·15=0·85

x=0·85/2=0·425

ii) 7x-2y=20

7(0·425)-4(-4·05)=20

20=20

hence proved