SOLUTION: Please help me figure out how to do this problem. Thanks sqrt(x+21) =5

Question 90474: Please help me figure out how to do this problem. Thanks
sqrt(x+21) =5
Answer by bucky(2189) (Show Source): You can put this solution on YOUR website!
Problem:
.

.
solve for x.
.
Begin by squaring both sides. When you do that the equation becomes:
.

.
which becomes:
.

.
solve for x by subtracting 13 from both sides to get:
.

.
The solution, therefore, is
.
Check by substituting 12 for x in the original equation:
.

.
Add the terms in the parentheses:
.

.
The square root of 25 results in +5, so the equation is true and the answer x = 4 works.
.
This is the third problem of this type that you posted. By now you should have become
familiar with the process of solving equations of this type. Just remember that when you
square a square root of a quantity, the result is just the quantity itself. For example,
the square of the square root of B is just B itself. If you are familiar with the exponential
form of roots and the way to multiply exponents you can look at problems of this sort in
the following way:
.
The square root of a quantity is the same as the quantity raised to the exponent .
.
In this problem the quantity is . To take the square root you just raise this
quantity to the power and this is the same as the square root. This can be
written as:
.

.
Then you can square the right side of this (squaring the square root of (x + 21) by multiplying
the right side by itself. In other words the right side is squared if you do the following
multiplication:
.

.
And by the rules of exponents to multiply these two quantities you just add the two exponents
to get:
.

.
If you follow this, then you can say that the square of equals .
.
Hope this also helps you to understand the problem a little better.
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