How do you solve 3t^2 – 4t = –30 by completing the square?

1 Answer
Nallasivam V
Jul 15, 2017

t=(2+-i sqrt(86))/3

Explanation:

Given -

3t^2-4t=-30

Divide all the terms by 3

(3t^2)/3-(4t)/3=(-30)/3

t^2-4/3t=-10

divide -4/3 by 2. square it and add it on both sides

It is -4/3-:2; -4/3xx1/2=-4/6

Square the value. It is (-4/6)=16/36=4/9

Add 4/9 to both sides

t^2-4/3t+4/9=-10+4/9=(-90+4)/9=(-86)/9

(t-2/3)^2=-86/9

t-2/3=+-sqrt((-86)/9)

t-2/3=sqrt(-86)/3

t=2/3+-(i sqrt(86))/3

t=(2+-i sqrt(86))/3

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