2x ^2-x=6.......i need help?

Question

solve for x by completing the square.
i think you're supposed to set it = to 0 then use the quadratic formula.

Answer 1

2x^2-x=6
Divide both sides by 2.
x^2-1/2x=3
x^2-1/2x+1/16=3+1/16
(x-1/4)^2=49/16
x-1/4=7/4 or -7/4
x=2 or -3/2

Answer 2

Completing the square does not require using the quadratic equation at all. You simply need to add/subtract equivalent values to allow for the factoring of the polynomial. In most cases, your factorization will not equal zero.

2x^2 - x = 6

x^2 - (1/2)x = 3


Complete the square by squaring half of the coefficient of x (1/2). [(1/2) / 2]^2 = [1/4]^2 = 1/16

x^2 - (1/2)x + (1/16) = 3 + (1/16)

(x - 1/4)^2 = 49/16


Take the square root of both sides....

x - 1/4 = ±7/4

x = 7/4 + 1/4 OR x = -7/4 + 1/4

x= 8/4 = 2 OR x = -6/4 = -3/2

x = {-3/2, 2}

Answer 3

2x^2-x=6
=> x^2-x/2 =3 [dividing both sides by 2]
=>(x)^2-2.*x*1/4+(1/4)^2=3+1/16 [adding 1/16 to both sides]
=>(x-1/4)^2=49/16
=>x-1/4=+-7/4 [square rooting both sides]
=>x=1/4+7/4 or 1/4-7/4=2 or -1 1/2

Answer 4

Yes.
2x^2 -x - 6 =0
d=b^2- 4ac=(-1)^2 - 4*2*(-6)=1+48=49
1X2=-b+-qdr d/2a = 1 +- 7/4 =>
=> X1=1+7/4=8/4=2 and X2=1-7/4=-6/4=-3/2.
So the solutions are: 2 and -3/2. :)

Answer 5

You are right.
Re-write the formula as

2x^2 -x - 6 = 0

You can factor this equation into
(2x +3)(x - 2)

Answer 6

so 2 squared = 4. 4x2 =8.
8-x=6
add x on both sides.
8=6 + x
subtract 6
2=x

Answer 7

2x^2-x-6=0

(2x+3)(x-2)=0

2x=-3 x=-2/3
x-2=0 x=2