Question

solve the following pair of linear equation in both substitution and elimination methods .

1.3x+4y=10 and 2x-2y=2
2.3x-5y-4=0 and 9x=2y+7
I surely mark as brainliest but who is answering first

Answer 1

Hii friend,

3X + 4Y = 10.......(1)

2X-2Y = 2...........(2)


From equation (1) we get,

3X+4Y = 10

3X = 10-4Y

X = 10-4Y/3........(3)

Putting the value of X in equation (2)

2X-2Y = 2

2×10-4Y/3 - 2Y = 2

20-8Y/3 - 2Y = 2

20-8Y - 6Y = 6

-14Y = 6-20

-14Y = -14

Y = 14/14 = 1

Putting the value of Y in equation (3)

X = 10-4Y/3

= 10-4×1/3 = 6/3 = 2.

(2) 3X - 5Y = 4.......(1)

9X -2Y = 7......(2)


From equation (1) we get,

3X - 5Y = 4

3X = 4+5Y

X = 4+5Y/3......(3)


PUTTING THE VALUE OF X IN EQUATION (2)

9X -2Y = 7

9 × 4+5Y/3 - 2Y = 7

3(4+5Y) - 2Y = 7

12 + 15Y - 2Y = 7

13Y = 7-12

Y = -5/13

PUTTING THE VALUE OF Y IN EQUATION (3)

X = 4+5Y/3

= 4+5×-5/13 / 3

= 4-25/13 / 3 = 52-25/13/3 = 27/13/3 = 81/3 = 27.


HOPE IT WILL HELP YOU... :-)