Question

9x -7y = 33
7x -9y = 15

Answer 1

x = 6

y = 3

Explanation:

To find the value of x & y, use add and subtract method.

• First, add the two equations and form a new equation.

9x - 7y = 33 ---------------------(I)

7x - 9y = 15 ---------------------(II)

16x - 16y = 48

Divide the entire equation by 16.

x - y = 3 -------------------(A)

• Subtract equation (II) from equation (I)

9x - 7y = 33

7x - 9y = 15

- + -

2x + 2y = 18

Divide the entire equation by 2.

x + y = 9 ------------------------(B)

• Add the equation (A) & (B),

x - y = 3

x + y = 9 {Now add}

2x = 12

Divide by 2,

x = 12 ÷ 2

`\boxed{\bf x = 6}`

• Substitute x = 6 in equation (B),

6 + y = 9

y = 9 - 6

`\boxed{\bf y = 3}`

Answer:

x = 6

y = 3