A maxm speed of 55 mph means that the speed has to be lexx than or equal to 55
x <= 55
Ermm, Don't you think it's 60?
Cause in my caculatons it's 60
- Zero Product Property: if a × b = 0, then either a or b = 0 or both a and b = 0.
(Make sure to set f(x) to zero)
So for this equation, I will be factoring by grouping. Firstly, what two terms have a product of -5x^2 and a sum of 4x? That would be 5x and -x. Replace 4x with 5x - x: 
Next, factor 5x^2 + 5x and -x - 1 separately. Make sure that they have the same quantity on the inside: 
Now you can rewrite the equation as: 
Now apply zero product property to the factors to solve for x:

<u>The x-intercepts are (1/5 ,0) and (-1,0).</u>
Answer:
A=SqRt(c^2-b^2)
Step-by-step explanation:
a^2 + b^2 = c^2
rearrange to solve for a^2
a^2= c^2-b^2
take the square root of each side
a= square root (c^2-b^2)