Answer:
a: x = 17
b: x = 17
d: x = 4
Explanation:
For a: the two angles add up to 90°, so use the equation
2x + 3x - 5 = 90 now solve for x...
5x = 85
x = 17
For b: the two angles make a straight line, so their sum is 180°, use the equation
6x + 3 + 4x + 7 = 180 now solve for x...
10x = 170
x = 17
For d: the two angles are vertical angles, so they are equal in measure, use the equation
5x - 3 = 3x + 5 now solve for x
2x = 8
x = 4