SOLUTION: If the square of a number increased by the number is 42, then what is the number? I have x^2+x=42, but I do not know if this is correct and if so, what to do after that

Question 630090: If the square of a number increased by the number is 42, then what is the number?
I have x^2+x=42, but I do not know if this is correct and if so, what to do after that
Found 3 solutions by Alan3354, graphmatics, josmiceli:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
If the square of a number increased by the number is 42, then what is the number?
I have x^2+x=42, but I do not know if this is correct and if so, what to do after that
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(x+7)*(x-6) = 0
x = -7, or x = 6

Answer by graphmatics(170)   (Show Source): You can put this solution on YOUR website!
Your equation is correct. Simply move the 42 to the left side of the equation as -42 to get . Now apply the quadratic equation.

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=169 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 6, -7. Here's your graph:

6 is the solution.
Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!
That is correct

complete the square
Take 1/2 of the coefficient of
, square it, and add it
to both sides

Take the square root of both sides

The number is 6
check:

OK
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