Quadratic Equation Question?

Question

I need to solve x^2-6x-7 = 0 through quadratic formula .. I got to this so far:

x=6+/-(square root)22 (over 2) I don't know how to simplify further or write it as current? Can someone help me? I basically need my two simplified coordinates and some work shown.

Thanks

Answer 1

The quadratic formula goes: (-b ± √b² - 4ac)/ 2a
So x²=a, -6x=b, -7=c
Now plug it in:
[-(-6) ± √(6)² -4(1)(-7)]/ 2(1)
simplify: (6± √36 + 28)/ 2
simplify further: (6±√64)/2
which equals: (6±8)/2
and if you separate it out: (6-8)/2 = -1 and (6+8)/2 = 7

Answer 2

I think you've done some miscalculations for your equation. x = 6 is correct because -(-6) = 6 but the rest of your simplified equation needs some help.

Quadratic equation is :
x = -b + or - sqr( b^2 - 4ac)/2a

Remembering to Please Excuse My Dear Aunt Sally.

b^2 = 36 because neg * neg = pos

-4 * a = -4

-4 * -7 = 28

36 - 28 = 8

The over 2 is correct because 2 * 1 = 2

So therefore x = 6 + sqr(8)/2 and x = 6 - sqr(8)/2

Answer 3

You're close, but you made a mistake in settign up your quadratic formula. a=1, b=-6, c=-7
[-b +/- sqrt(b^2 - 4ac)] / 2a

[6 +/- sqrt(-6^2 - 4(1)(-7))] / 2(1)

[6 +/- sqrt(36 - (-28))] / 2

[6 +/- sqrt(26 + 28)] / 2

[6 +/- sqrt(64)] / 2

[6 +/- 8] / 2

x = -1 or x = 7

Answer 4

X= -b +/- the square root of ((b^2)-4ac)/2a

X= 6 +/- The square root of ((-6^2)-4*1*-7)/2*1

X= 6 +/- The square root of (36+28)/2

X= 6+/- the square root of (64)/2

X=(6+/- 8)/2

X= 6+8/2

X= 14/2

X= 7

X= 6-8/2

X= -2/2

X=-1

Answer 5

That should be good enough. If you want you can combine the terms in something like (12+/-sqrt(22))/2, but any teacher I know of should accept what you got.

Answer 6

x^2 - 6x - 7 = 0

x = (-b ± sqrt(b^2 - 4ac))/(2a)

x = (-(-6) ± sqrt((-6)^2 - 4(1)(-7)))/(2(1))
x = (6 ± sqrt(36 + 28))/2
x = (6 ± sqrt(64))/2
x = (6 ± 8)/2
x = (14/2) or (-2/2)
x = 7 or -1

You have your formula as

x = (-b ± sqrt(b - 4ac))/(2a)

which is incorrect.

Answer 7

-6 +- sqr (36-4(1)(-7))/2(1)
-6 +- sqr (64)/2
ans:1 and -7