12x - 4 (12x - 5) = 1/3 (6x - 15)

Question

Needs to be solved for X. I don’t understand how to do it so if you could include the steps and why you do everything I would really appreciate it thank you. My teacher gave the answer that x= -25/8 but idk how to get it.

Answer 1

try -25/8, plug it into the given equation

12(-25/8) -4(12(-25/8 -5)= 1/3(6(-25/8 -15)

-75/4 -4(-75/4) +20 = 2(-25/8) - 3

3(75/4) + 20 = -50/8 -3

80/4+ 225/4 = -50/8 -24/8

305/4 = - 74/8 = - 37/4

just doesn't work

12x-4(12x-5) = (1/3)(6x-15)

12x -48x +20 = 2x -5

-36x = 2x-25

38x =25

x =25/38

unless the problem really was

12x-4(12x-5) = 1/3(6x-15) then

12x -48x +20 = 1/(18x -45)

-36x -20 = 1/(18x-45)

(-36x+20)(18x-45) = 1

-648x^2 +1620x + 360x -900 = 1

162x^2 +1980x + 224 = 0

x = about -12.1 and -0.1