Answer:
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Explanation:
Since A and b are complimentary angles There sum is equal to 90°
In other words:
We know A = (7x+18) and b = (5x-12)
Next, insert these values into the equation (A+ b = 90°):

Drop the () since we are not multiplying anything

Combine like terms: 7x and 5x, 18 and-12

Subtract 16 from both sides of the equation
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Divide by 12 and get:
or
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Hope this helps :)