Solve by using the quadratic formula. 3x^2-7x=3

Question

Thank you for your prior help!  Can you please explain this one?  Solve by using the quadratic formula.  3x^2-7x=3

Answer 1

First rearrange:  3x² - 7x - 3 = 0

 

Quadratic formula:  from ax² + bx + c = 0 

 

                             to  x = [-b (+ or -) sqrt(b² -4ac)]/2a

 

x = [-(-7) (+ or -) sqrt((-7)² -4(3)(-3))]/2(3) 

 

x = [7 (+ or -) sqrt(49 + 36)]/6

 

x = (7 + sqrt(85))/6  and x = (7 - sqrt(85))/6

 

 

Answer 2

Hi Abby;

3x^2-7x=3

We want everything on one side, so we subtract 3 from both sides...

3x²-7x-3=0

Quadratic formula...

x=[-b+/-√(b²-4ac)]/2a

b²-4ac

(-7)²-[(4)(3)(-3)]

49-(-36)

49+36

85

x=(--7+/-√85)/[(2)(3)]

x=(7+/-√85)/6