Answer: x = 5
Step-by-step explanation:
The area of a rectangle is the length times the width. Since the dimensions are given as functions of x, youre going to have to use FOIL to combine them, then set that answer equal to the given value of 72.
l*w = (x+3)*(x+4) = x^2 + 7x +12 = 72
Subtract 72 on both sides. There is a reason why we'll do this instead of subtracting 12. The quadratic formula will help us to solve for x.
x^2 + 7x - 60 = 0
Apply the quadratic formula

We cant have a negative x value because that would result in negative dimensions and a negative area, which is impossible in this context. So you want to add the 17 instead of subtracting it.
x = 5 and x = -12
An alternate way is just factoring the trinomial to:
(x+12)(x-5) = 0
Answer:
The answer is that x = 6 and y = -6
Step-by-step explanation:
In order to find these values, we can use elimination. To do so, we multiply the first equation by 2 and then add the equations together.
4x + 8y = -24
-4x - 2y = -12
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6y = -36
y = -6
Now that we have this value, we can plug the value into one of the originals and find x.
2x + 4y = -12
2x + 4(-6) = -12
2x - 24 = -12
2x = 12
x = 6
Answer:
4
Step-by-step explanation:
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Many lines do. One of them would be y = 2x