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5 votes
A and B are complementary angles. If mA = (2x + 30)° and mB = (7x – 3), then find the measure of B.

User Greig
by
7.5k points

2 Answers

4 votes

Answer:

The measure of B is 46°

Explanation:

To solve this equation, you need to add the two equations, and set them equal to 90° since they are complementary angles

2x+30+7x-3=90

You also need to add like terms, so 2x+7x and 30+-3, or 30-3

9x+27=90

Then you need to isolate the variable by subtracting 27 from both sides

9x+27-27=90-27

=

9x=63

Then you need to divide both sides by 9 to get x=7

Since we know what x is, we plug x into the equation (7x-3) and we will now have 7(7)-3.

To solve this, we multiply 7 and 7, and subtract 3 to get 46.

So the answer is mB=46

I hope this helps!!

User Donn Felker
by
6.2k points
7 votes

Answer:

mB=46

Explanation:

2x+30+7x-3=90

Combine like terms

9x+27=90

Subtract by 27 on both sides

9x=63

Divide by 9 on both sides

x=7

mB=(7x-3)

Substitute 7 for x

mB= 7(7)-3

mB= 49-3

mB=46

User Binarez
by
7.0k points
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