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:
30
Step-by-step explanation:
Answer:
each movie costs $2.75, each video game costs $6.75
Step-by-step explanation:
x = movies, y = video games
7x + 9y = 80
5x + 3y = 34
simplified to
x = 11/4 , y = 27/4
9514 1404 393
Answer:
sometimes
Step-by-step explanation:
4 + 7 = 11 . . . not a multiple of 7
28 + 7 = 35 . . . a multiple of 7
If you add a multiple of 4 and a multiple of 7, the sum is <u>sometimes</u> a multiple of 7.
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It will be a multiple of 7 when the multiple of 4 used is a multiple of 7, such as 4×7 or 4×14 or 4×21, for example.
Answer:
$1,800
Step-by-step explanation:
If Michael works 30 hours a week for $15 an hour we can use the equation:
15 x 30 = 450.
Now just multiply the given answer by 4 and you're left with:
450 x 4 = 1800.