Solve 2x

2
+6x−60=20 by factoring and using the zero product property.

x=5, −8

x=−5, 8

x=10, −3

x=−10, 3

1 answer

To solve the equation \( 2x^2 + 6x - 60 = 20 \) by factoring, we first need to set the equation to zero:

\[ 2x^2 + 6x - 60 - 20 = 0 \] \[ 2x^2 + 6x - 80 = 0 \]

Next, we can simplify the equation by dividing every term by 2:

\[ x^2 + 3x - 40 = 0 \]

Now, we can factor the quadratic. We are looking for two numbers that multiply to \(-40\) (the constant term) and add to \(3\) (the coefficient of the linear term).

The numbers that satisfy this condition are \(8\) and \(-5\). Thus, we can factor the equation as follows:

\[ (x + 8)(x - 5) = 0 \]

Using the zero product property, we set each factor equal to zero:

  1. \(x + 8 = 0 \implies x = -8\)
  2. \(x - 5 = 0 \implies x = 5\)

Thus, the solutions to the equation are:

\[ x = 5, -8 \]

So the correct answer is:

x = 5, -8.