Answer:
One possible equation is (6b+2)+40 = 90
That equation solves to b = 8
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Step-by-step explanation:
The angles (6b+2) and 40 degrees combine to form a right angle, aka 90 degree angle. This is because the upper angle is 90 degrees, so the remaining portion is 180-90 = 90.
So (6b+2)+40 = 90 is one possible equation.
Let's solve for b.
(6b+2)+40 = 90
6b+42 = 90
6b = 90-42
6b = 48
b = 48/6
b = 8
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A slight alternative.
The angles (6b+2), 40, and the 90 degree angle form a straight line.
The three angles add to 180
(6b+2)+(40)+(90) = 180 is another possible equation
6b+132 = 180
6b = 180-132
6b = 48
b = 48/6
b = 8