Question

What is the solution of the system of equations below?
x + 3y = 7
2x - y = 7

Answer 1

y = 1

x = 4

Explanation:

x + 3y = 7 → ( 1 )

2x - y = 7 → ( 2 )

First, let us make x the subject in equation ( 1 ).

x = 7 - 3y → ( 3 )

Let us find the value of y.

For that let us take equation (1) & replace x with ( 7 - 3y ).

2x - y = 7

2 ( 7 - 3y ) - y = 7

Solve the brackets.

14 - 6y - y = 7

Combine like terms.

14 - 7y = 7

Subtract 14 from both sides.

-7y = 7 - 14

-7y = -7

Divide both sides by -7.

y = 1

Let us find value of x

For that let us take equation (3) & replace y with 1.

x = 7 - 3y

x = 7 - 3 × 1

x = 7 - 3

x = 4