How do you solve 2/3 x^2 + 1/4 x= 323x2+14x=3?

1 Answer
May 17, 2018

See a solution process below:

Explanation:

First, multiply each side of the equation by color(red)(12)12 to eliminate the fractions:

color(red)(12)(2/3x^2 + 1/4x) = color(red)(12) xx 312(23x2+14x)=12×3

(color(red)(12) xx 2/3x^2) + (color(red)(12) xx 1/4x) = 36(12×23x2)+(12×14x)=36

8x^2 + 3x = 368x2+3x=36

Next, put the equation in standard quadratic form:

8x^2 + 3x - color(red)(36) = 36 - color(red)(36)8x2+3x36=3636

8x^2 + 3x - 36 = 08x2+3x36=0

We can nowuse the quadratic equation to solve this problem:

The quadratic formula states:

For color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0ax2+bx+c=0, the values of xx 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))x=b±b2(4ac)2a

Substituting:

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

color(blue)(3)3 for color(blue)(b)b

color(green)(-36)36 for color(green)(c)c gives:

x = (-color(blue)(3) +- sqrt(color(blue)(3)^2 - (4 * color(red)(8) * color(green)(-36))))/(2 * color(red)(8))x=3±32(4836)28

x = (-color(blue)(3) +- sqrt(9 - (-1152)))/16x=3±9(1152)16

x = (-color(blue)(3) +- sqrt(9 + 1152))/16x=3±9+115216

x = (-color(blue)(3) +- sqrt(1161))/16x=3±116116

x = (-color(blue)(3) +- sqrt(9 * 129))/16x=3±912916

x = (-color(blue)(3) +- sqrt(9)sqrt(129))/16x=3±912916

x = (-color(blue)(3) +- 3sqrt(129))/16x=3±312916

x = (3(-1 +- sqrt(129)))/16x=3(1±129)16

Or

x = 3/16(-1 +- sqrt(129))x=316(1±129)