2x-y=5 and 9x +4y=22 solve by substitution

Question

solve the problem by substitution.

Answer 1

Substitution method

Given first equation 2x-y = 5

Subtract 2x from each side.

2x-2x-y = 5-2x

-y = 5-2x

Multiple to each side by negitive one.

y = 2x-5 ---> (1)

Given second equation is 9x+4y = 22 ---> (2)

From (1) substitute the y value in (2).

9x+4(2x-5) = 22

9x+8x-20 = 22

17x-20 = 22

Add 20 to each side.

17x = 42

Divide to each side by 17.

⇒ x = 42/17

Substitute the x value in (2).

9(42/17)+4y = 22

372/17+4y = 22

4y = 22-378/17

4y = -4/17

⇒ y = -1/17

Solution x = 42/17, y = -1/17.