SOLUTION: Can someone please help me with these? Please? Give exact and approximate solutions to three decimal places. x^2-7x+9=0 x^2+8x+16=49 (x-8)^2=81

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Question 469000: Can someone please help me with these? Please?
Give exact and approximate solutions to three decimal places.
x^2-7x+9=0
x^2+8x+16=49
(x-8)^2=81
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
x2-7x+9=0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B-7x%2B9+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-7%29%5E2-4%2A1%2A9=13.

Discriminant d=13 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--7%2B-sqrt%28+13+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-7%29%2Bsqrt%28+13+%29%29%2F2%5C1+=+5.30277563773199
x%5B2%5D+=+%28-%28-7%29-sqrt%28+13+%29%29%2F2%5C1+=+1.69722436226801

Quadratic expression 1x%5E2%2B-7x%2B9 can be factored:
1x%5E2%2B-7x%2B9+=+1%28x-5.30277563773199%29%2A%28x-1.69722436226801%29
Again, the answer is: 5.30277563773199, 1.69722436226801. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-7%2Ax%2B9+%29

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x2+8x+16=49
x2+8x-33=0
(x+11)(x-3)
x=-11 or 3
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(x-8)2=81
x2-16x+64=81
x2-16x-17=0
(x+1)(x-17)=0
x=-1 or 17..