35
this is the correct answer if you're on usatestprep
So for this trinomial, I will be factoring by grouping. Firstly, what two terms have a product of 16x^2 and a sum of 10x? That would be 8x and 2x. Replace 10x with 2x + 8x:
Next, factor x^2 + 2x and 8x + 16 separately. Make sure that they have the same quantity inside the parentheses: 
<u>Now you can rewrite this as 
, which is your final answer.</u>
Let's give Cindy's age a variable.
Cindy's age = x
Cindy multiplies her age by 5
x(5)
Subtracted by 12
x(5) - 12
Divide by 3
(5x - 12)/3
The result was 16
(5x - 12)/3 = 16
Let's solve
Multiply both sides by 3
(5x - 12) = 48
Open brackets
5x - 12 = 48
Add 12 to both sides
5x = 60
Divide by 5 on both sides to isolate x
x = 12
Cindy is 12 years old.
0=x^2-3x-28 gives x=7 or x=-4. These are the x-intercepts. The y-intercept is when x is 0. y=(0)^2-3(0)-28. The y-intercept is -28.
