quadratic equations

[Guest]

I am having trouble with quadratic equations:

x^2+7x-7/2=0

This is what I did: 7 + or - sqrt63/2 and got x=24.5, -35.5, but it was wrong

x^2+6x+11=0

I did the same thing with the quadratic formula and got x=-11, 5, but it was wrong

0.1x^2-0.8x-2=0

I got x=8, -6.4 but it was wrong

 

[tkhunny]

I am having trouble with quadratic equations:

x^2+7x-7/2=0

This is what I did: 7 + or - sqrt63/2 and got x=24.5, -35.5, but it was wrong

You are very close. I think you may be having an order problem.

First, however, that's -7, not +7.

(-7 + sqrt(63))/2 = (-7 + sqrt(9*7))/2 = (-7 + 3*sqrt(7))/2 = 0.46862697

Note: Add more parentheses to clarify meaning.