Question

solve -x+4y=7; 5x+4y=7​

Answer 1

Answer:

X+4y=7

5x+4y=7. (subtracting)

- - -

....................

-4y= 0

y=-1/4

so, X=7-4y

=7-4x-1/4

=7+1

=8 ✓✓

Answer 2

Equation 1)

= -x+4y=7

= -x =7 - 4y

= x = -7 + 4y

Eqaution 2)

= 5x+4y=7

= 5x = 7 - 4y

= x = 7-4y/5

On comparing equation 1 & 2

= -7 + 4y = 7-4y/5

= 5(-7 + 4y) = 7- 4y

= -35 + 20y = 7 - 4y

= 20y + 4y = 7 + 35

= 24y = 42

= y = 42/24

= y = 7/4

Put y = 7/4 in eq 1

= x = -7 + 4y

= x = -7 + 4 × 7/4

= x = -7 + 7

= x = 0

So, y = 7/4 and x = 0

Thank you! :]