Answer: 20
explanation: simplify the radical by breaking the radicand up into a product of known factors, assuming positive real numbers
Answer:

Step-by-step explanation:
Perimeter is 2(2x+5)+2(x-2) which is 4x+10+2x-4 which is in turn 6x+6. 6x+6 is the perimeter. Hope I helped!
Since x is the number of seconds it took the rock to hit the water, x is the value that we are looking for. When the rock hits the water, it's height is 0, therefore, f(x) = 0. So, we can set the expression on the right equal to 0, and solve for 0. Let's do just that:

We can divide by -16, nothing will happen because 0 divided by anything is 0:

To factor any trinomial in standard form (given below), we must find two numbers that add to "b" and multiply to "c":

So, for this specific question, let's find two numbers that add to -8 and multiply to 9. These are clearly 9 and -1. We can write it in this way now:

Both answers would be valid, but there can't be negative time, so your answer is
"It takes 9 seconds for the rock to reach the water."
So you have (1/4)n-16
to bring out the 1/4, you have to divide 1/4 from every term.
(1/4)n/(1/4)=n
16/(1/4)=64
Thus you get (1/4)(n-64)