Answer:
50
Step-by-step explanation:
The sign only changes when divided or multiplied by a negative number.
Answer: x=30
Step-by-step explanation:
The sum of the angles must be 360.
4x+3x+3x+2x = 12x
12x = 360
x =360/12 = 30
The aluminum section's area formula solved for h is 
From the complete question, the expression of the area (A) in terms of variables a, b and h is:

Factor out h from the expression on the right-hand side

Divide both sides of the equation by (a - b)

Remove the bracket

Rewrite the above equation as follows:

Hence, the aluminum section's area formula solved for h is 
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