Question

7x-4y=49;5x-6y=57 by elimination method

Answer 1

Answer:

X = 3 & Y = -7

7x - 4y = 49 ----------------------( 1 )

5x - 6y = 57------–---------------( 2 )

Multiply eq. (1) by 5 & eq. (2) by 7.

.°. 35x - 20y = 245 ----------------( 3 )

.°. 35x - 42y = 399 ----------------( 4 )

Subtract eq. ( 3 ) from eq. ( 4 )

(35x - 42y) - (35x - 20y) = 399 - 245

35x - 42y - 35x + 20y = 154

- 42y + 20y = 154

- 22y = 154

y = 154 / -22

y = -7

Putting the value of y in eq. ( 1 )

7x - 4y = 49

.°. 7x - 4 (-7) = 49

.°. 7x + 28 = 49

.°. 7x = 49 - 28

.°. 7x = 21

.°. x = 21 / 7

.°. x = 3