How do you solve 8m^2 - 2m = 7 using the quadratic formula?

1 Answer
Jun 3, 2018

See a solution process below:

Explanation:

First, put the equation in standard form:

8m^2 - 2m - color(red)(7) = 7 - color(red)(7)

8m^2 - 2m - 7 = 0

We can now use the quadratic equation to solve this problem:

The quadratic formula states:

For color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0, the values of x which are the solutions to the equation are given by:

x = (-color(blue)(b) +- sqrt(color(blue)(b)^2 - (4color(red)(a)color(green)(c))))/(2 * color(red)(a))

Substituting:

color(red)(8) for color(red)(a)

color(blue)(-2) for color(blue)(b)

color(green)(-7) for color(green)(c) gives:

x = (-color(blue)(-2) +- sqrt(color(blue)(-2)^2 - (4 * color(red)(8) * color(green)(-7))))/(2 * color(red)(8))

m = (2 +- sqrt(4 - (32 * color(green)(-7))))/16

m = (2 +- sqrt(4 - (-224)))/16

m = (2 +- sqrt(4 + 224))/16

m = (2 +- sqrt(228))/16

m = (2 +- sqrt(4 * 57))/16

m = (2 +- sqrt(4)sqrt(57))/16

m = (2 +- 2sqrt(57))/16

m = 2/16 +- (2sqrt(57))/16

m = 1/8 +- sqrt(57)/8

m = (1 +- sqrt(57))/8

The Solution Set Is:

m = { ((1 - sqrt(57))/8), ((1 + sqrt(57))/8)}