Answer:
To find critical points, take the first derivative and set it equal to zero:
f(x) = -2x^2 + 4x + 5
f'(x) = -4x + 4
-4x+4 = 0
-4x = -4
x = 1
Critical point at x = 1
Alternatively, if you mean zeros, or where the x intersects, you can use the quadratic equation.
Answer:
x+5
Step-by-step explanation:
Since you don't know how much Joe weighs, you can express his weight as x. Then, you add on 5 because you have 5 more lbs than joe (which is x).
Answer:

or

Step-by-step explanation:
Divide the numerator and the denominator by the same number:

or
Multiply the numerator and the denominator by the same number:

Answer:
0.84
Step-by-step explanation:
Divide 63 by 75 and you get 0.84 (84%).