The correct answer is d15
A = (1/2) b * h
h = b - 5
42 = (1/2) * b * (b - 5)
42 = (1/2) * b^2 - 5b
multiply both sides by 2 to clear the fraction (1/2)
2(42) = 2(1/2) *b^2 - 5b
84 = b^2 -5b
Since this is a quadratic equation, subtract 84 from both sides so that it is set = to zero.
b^2 - 5b - 84 = 0
Now factor.
(b - 12)(b + 5) = 0
b - 12 = 0; b = 12
b + 5 = 0; b = -5
You can't have a negative length so the answer is 12m
To check the answer:
A = (1/2) * 12* 7
A = 42 m^2
Answer:
First option and Last option are the correct choices.
Step-by-step explanation:
Thanks!
Answer: x=2
Step-by-step explanation:
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We are given the equations 3x+5y=-3 and x-5y=-5.
Both equations have a 5y term which allows us to easily solve the system by elimination. To do so we will add the equations together like a simple addition problem by adding the x terms together, the y terms together, and the integer answers together.
3x + 5y = -3
+x - 5y = -5
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4x + 0y = -8
The y terms cancel out since one is positive and one is negative. Now we can solve for x.
4x = -8

x = -2
Now plug -2 in for x in one of the original equations to find y.
(-2) - 5y = -5
-5y = -3
y = 3/5
Our answer as an ordered pair is (2, 3/5)