We can use the FOIL method to solve.
(5x + 3)(7x - 7)
(5x * 7x) + (5x * -7) + (3 * 7x) + (3 * -7)
35x - 35x + 21x - 21
0 + 0
0
Best of Luck!
The unit rate for the 1st one is: $0.19 / ounce
The unit rate for the 2nd one is: $0.16 / ounce
The 36 ounce box would be the better buy because it is less per ounce than the 24 ounce box
To find the y-intercept, simply set the value of x equal to 0, and solve for y, or f(x).
f(x) = 0^2 - 3(0) - 40
f(x) = -40
<h3>The y-intercept is -40.</h3>
Because this is a 2nd degree polynomial, we cannot find the x-intercepts in one step, and must instead use one of a few different methods.
In this case, we're going to use the quadratic formula:

Plug in the values.
3 +/- √(-3^2 + 160) / 2
3 +/- √169 / 2
3 +/- 13 / 2
(3 + 13) / 2 = 16 / 2 = 8
(3 - 13) = -10 / 2 = -5
<h3>The x intercepts are 8, and -5.</h3>
1) 2a = 9b ⇒ 2:9
2) a + b = 3b ⇒ a = 2b ⇒ 1:2
Answers: 2:9 and 1:2