Question 686982: An integer plus three times the square of the integer is 10.find the integer.
Answer by josh_jordan(263)   (Show Source):
You can put this solution on YOUR website! To solve this, let's first set this problem up as an equation:
An integer plus three times the square of the integer is 10, can be set up as:
As you can see, this is a quadratic equation. If we subtract the 10 from both sides, it will be set up in standard quadratic form, and we will be able to factor:
When we solve for x in the first set of parenthesis, we see that x equals 5/3. 5/3 is not an integer, therefore it cannot be part of the solution.
When we solve for x in the second set of parenthesis, we see that x = -2. -2 IS an integer.
Therefore, -2 is our answer. To validate, substitute -2 for x in our original equation:
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