Question

if (3x+18) and (2x-8) are supplementary angle then find x
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Answer 1

Answer:

Angle 1 = 3x + 18

Angle 2 = 2x - 8

The angles are supplementary

then (3x + 18) + (2x - 8) = 180

5x + 10 = 180

5x = 170

x = 34°

Angle 1 = 34° × 3 = 102° + 18 = 120°

Angle 2 = 2 × 34° - 8 = 60°

Answer 2

• Supplementary angles are The angles that sum up to 180°

Now as angles sum up to 180°, the equation becomes :

(3x + 18) + (2x - 8) = 180°

⇒ 3x + 18 + 2x - 8 = 180°

⇒ 3x + 18 + 2x - 8 + 8 = 180° + 8

⇒ 3x + 18 + 2x = 188°

⇒ 3x + 18 + 2x - 18 = 188° - 18

⇒ 3x + 2x = 170°

⇒ 5x = 170°

⇒ x = 170°/5

⇒ x = 34°