7x³ = 28x is our equation. We want its solutions.
When you have x and different powers, set the whole thing equal to zero.
7x³ = 28x
7x³ - 28x = 0
Now notice there's a common x in both terms. Let's factor it out.
x (7x² - 28) = 0
As 7 is a factor of 7 and 28, it too can be factored out.
x (7) (x² - 4) = 0
We can further factor x² - 4. We want a pair of numbers that multiply to 4 and whose sum is zero. The pairs are 1 and 4, 2 and 2. If we add 2 and -2 we get zero.
x (7) (x - 2) (x + 2) = 0
Now we use the Zero Product Property - if some product multiplies to zero, so do its pieces.
x = 0 -----> so x = 0
7 = 0 -----> no solution
x - 2 = 0 ----> so x = 2 after adding 2 to both sides
x + 2 = 0 ---> so = x - 2 after subtracting 2 to both sides
Thus the solutions are x = 0, x = 2, x = -2.
Parallel lines have equal/same slopes
Answer:
B
Step-by-step explanation:
B. 36
because if you find the area of the big square its 5×6 and the smaller rectangle is 3×2
so its 30+6
36
12 minutes because it is three miles into for the train to go completely in and out (one mile for the nose to enter, on mile for the nose to exit and tail enter, and one mile for tail to exit). 3/15=x/60
