Find the values of x and y.

The value of x is 10 and y is 20.

Solution:

Sum of the adjacent angles in a straight line = 180

⇒ 7x° + 90° + 20° = 180°

⇒ 7x° + 110° = 180°

Subtract 110° from both sides.

⇒ 7x° = 70°

Divide by 7 on both sides.

⇒ x° = 10°

In the image, 90° and (5x° + 2y°) are vertically opposite anlges.

If two lines are intersecting, then vertically opposite angles are equal.

⇒ (5x° + 2y°) = 90°

⇒ 5(10°) + 2y° = 90°

⇒ 50° + 2y° = 90°

Subtract 50° from both sides.

⇒ 2y° = 40°

Divide by 2 on both sides.

⇒ y° = 20°

Hence the value of x is 10 and y is 20.

-2

7 - 9 = -2

reversed:

-2 + 9 = 7