SOLUTION: I need some help with this problem. I have tried to work it and cannot seem to come up with the answer All the directions say is to complete the square to solve the following equa

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Question 148962: I need some help with this problem. I have tried to work it and cannot seem to come up with the answer All the directions say is to complete the square to solve the following equations
x^2+6x=7 ( i know that you need to get every thing on 1 side but then what)
x^2+6x-7=0

and with this problem the same directions but would you us the quadratic formula to solve? 2x^2-5x-3=0 Thanks Leann
Found 2 solutions by ankor@dixie-net.com, mangopeeler07:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
I need some help with this problem. I have tried to work it and cannot seem to come up with the answer All the directions say is to complete the square to solve the following equations
x^2+6x=7 ( i know that you need to get every thing on 1 side but then what)
x^2+6x-7=0
:
If they want you to solve by completing the square you can leave 7 on the right
And find the value that will complete the square
:
x^2 + 6x + __ = 7
:
To find the term that will complete the square,
divide the coefficient of x by 2 and square that. 6/2 = 3, 3^2 = 9, so we have:
;
x^2 + 6x + 9 = 7 + 9; we have to add 9 to both sides to preserve equality
:
x^2 + 6x + 9 = 16; we know that left side is (x+3)(x+3) or (x+3)^2, so we have:
:
(x + 3)^2 = 16
:
Find the square root of both sides;
x + 3 = +/-sqrt%2816%29
x + 3 = +/-4
Two solutions:
x = -3 + 4
x = +1
and
x = -3 - 4
x = -7
;
You can confirm that: FOIL (x-1)(x+7) = x^2 - 1x + 7x - 7 = x^2 + 6x - 7
:
:
and with this problem the same directions but would you us the quadratic formula to solve? 2x^2 - 5x - 3 = 0
:
you could use the quadratic formula, but this will factor to: (2x + 1)(x - 3)
:
If you insist on using the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
In your equation: a=2; b=-5; c=-3
x+=+%28-%28-5%29+%2B-+sqrt%28+-5%5E2-4%2A2%2A-3+%29%29%2F%282%2A2%29+
x+=+%285+%2B-+sqrt%2825+-+%28-24%29+%29%29%2F%284%29+
x+=+%285+%2B-+sqrt%2825+%2B+24+%29%29%2F%284%29+
x+=+%285+%2B-+sqrt%2849%29%29%2F%284%29+
Two solutions
x = %285+%2B+7%29%2F4
x = +3
and
x = %285+-+7%29%2F4
x = -1%2F2
:
:
Did this help you? Any questions?

Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
x^2+6x-7=0
Factor:
start with
(x)(x)
insert a + and a -
(x+)(x-)

Find two factors of 7 whose difference is 6: 7 and 1. insert them:
(x+7)(x-1)

Set each expression equal to zero
x+7=0
x-1=0
Solve for x in each
x=-7
x=1