Answer:
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Since ad, bc, and bd are integers since integers are closed under the operation of multiplication and ad-bc is an integer since integers are closed under the operation of subtraction, then (ad-bc)/bd is a rational number since it is in the form of 1 integer divided by another and the denominator is not eqaul to 0
Move all terms to one side
4w^2 + 49 + 28w = 0
Rewrite 4w^2 + 49 + 28w in the form a^2 + 2ab + b^2, where a = 2w and b = 7
(2w)^2 + 2(2w)(7) + 7^2 = 0
Use the Square of Sum: (a + b)^2 = a^2 + 2ab + b^2
(2w + 7)^2 = 0
Take the square root of both sides
3w + 7 = 0
Subtract 7 from both sides
2w = -7
Divide both sides by 2
<u>w = -7/2</u>
First, you have to find what 80% of 15 is. In order to do that you have to change 80% percent to decimal, which would be .80. Then, multiply .80 and 15 to get 12. Subtract 12 from 15 and your answer is 3.