Answer:
a) <5 and <7 have congruent angles. That means that both angles are equal, they have the same measure. This means that the measure of <7 is 47°.
<7 = 47°
b) 5 and 6 are adjacent, so this is the equation that we have to do to solve for the value of x.
<5 + <6 = 180°
47° + (2x - 5)° = 180°
c) To solve the linear equation we need to isolate x.
47° + (2x - 5)° = 180°
(2x - 5)° = 180° - 47° = 133°
2x - 5 = 133
2x = 133 + 5 = 138
x = 138/2 = 69