## john18sanders 2 years ago solve by completing the square: 4x^2-7x=3

1. nitz

do u know the method of completing the square first............?

2. nitz

firstly make the coefficient of first term ie,x^2 unity

3. Goten77

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4. Goten77

if all us fails.. u can even use the quadractic formula

5. Azteck

NO, the question says to complete the square. @Goten77 if you're good at maths then you should know to never make a rookie mistake of not obeying to the question.

6. Azteck

$4x^2-7x=3$ Divide both sides by 4! $x^2-\frac{7}{4}x=\frac{3}{4}$ Use this property of completing the square. $x^2-bx=c$ $(x-\frac{b}{2})^2=c+(\frac{b}{2})^2$ SO.... $(x-\frac{ 7 }{ 8 })^2=\frac{ 3 }{ 4 }+\frac{ 49 }{ 64 }$ $(x-\frac{ 7 }{ 8 })^2=\frac{ 97 }{ 64 }$ Square root both sides while BEING CAUTIOUS that there must be a negative value as well as a positive. $x-\frac{ 7 }{ 8 }=\frac{ \pm \sqrt{97} }{ 8 }$ $x=\frac{ \pm \sqrt{97} }{ 8 }+\frac{ 7 }{ 8 }$ $x=\frac{ 7\pm \sqrt{97} }{ 8 }$