Solve the quadratic equation; 2x^2 -15x = 0

Answer 1

2x² - 15x = 0, Use Zero-Product Rule

x(2x - 15) = 0

x = 0

or

2x - 15 = 0

Answer 2

Hi Lenny,

There are actually multiple ways to solve the quadratic equations by using the zero-product rule, the quadratic formula, completing the square, etc.

2x^2 - 15x

Just upon looking at the equation, it might be easier to use the zero-product rule to factor because both terms contain the variable x so it would make sense to isolate it.

Additionally, because we want to find the x-intercepts, y must be equal to zero so we can also set the entire expression to zero.

2x^2 - 15x = 0

x(2x - 15) = 0

For the expression to be equal to zero, one or both of the following two things must occur

1) x = 0

OR/AND

2) 2x - 15 = 0

2x = 15

x = 7.5

This means that there are two coordinates where the equation would be equal to zero (0,0) or (7.5, 0)

Just a quick note: You can also double check you work by substituting the values of x and seeing you if you get a value of zero for y.

Hope that helps!