Solve for x.
A) -9
C) -5
B) -11
D) 10

here's the answer to your question

D. 10

Step-by-step explanation:

Concept:

Here, we need to know the triangle sum theorem.

The Triangle Sum Theorem states that the sum of the three interior angles in a triangle is always 180°.

If you are still confused, please refer to the attachment below for a graphical explanation.

Solve:

According to the Triangle Sum Theorem:

∠1 + ∠2 + ∠3 = 180

Substitute the angle values

(60) + (50) + (7x) = 180

Combine like terms

110 + 7x = 180

SUbtract 110 on both sides

110 + 7x - 110 = 180 - 110

7x = 70

Divide 7 on both sides

7x / 7 = 70 / 7

x = 10

Hope this helps!! :)

Please let me know if you have any questions

need more info

step-by-step explanation: