Complete Question:
Triangle abc has the angle mesausres shown.
m<A = (2x)°
m<B = (5x)°
m<C = (11x)°
Which statement is true about the angles?
A. m<A = 20°
B. m<B = 60°
C. m<A and m<B are complementary
D. m<A + m<C = 120°
Answer:
A. m<A = 20°
Step-by-step explanation:
m<A + m<B + m<C = 180° (sum of interior angles of a triangle)
(substitution)
Solve for x. Add like terms.

Divide both sides by 18


Find the measure of each angle by substituting x = 10:
m<A = (2x)° = 2(10) = 20°
m<B = (5x)° = 5(10) = 50°
m<C = (11x)° = 11(10) = 110°
Therefore, the only true statement is:
A. m<A = 20°
You can use Substitution to solve this problem:
4x-y=20
-y=-4x+20
y=4x-20
Now you have two equations, and you use the first one to substitute into the second one.
y=4x-20 and -2x-2y=10
-2x-2(4x-20)=10
-2x-8x+40=10
-10x+40=10
-10x=-30
-x=-3
x=3
Now that we have figured out what x is, we can substitute x in to one of the equations to figure out y.
4x-y=20 x=3
4(3)-y=20
12-y=20
-y=8
y=-8
<em><u>So your answer would be x=3 and y=-8</u></em>