SOLUTION: hi, I am solving by quadraic formula -b sqrt (b2-4ac)/(2a)
x^2+2x=168
x^2+2x-168=168-168
x^2+2x-168=0
-2 +- sqrt (2^2-4(1)(-168)/(2(1))
-2 +- sqrt (4-672)/(2)
-2 +- sqrt
Algebra.Com
Question 409158: hi, I am solving by quadraic formula -b sqrt (b2-4ac)/(2a)
x^2+2x=168
x^2+2x-168=168-168
x^2+2x-168=0
-2 +- sqrt (2^2-4(1)(-168)/(2(1))
-2 +- sqrt (4-672)/(2)
-2 +- sqrt (668)/(2) This is where I am lost. It's not a perfect square, so
what do I do now? I choose factors.
-2 +- sqrt ((4(167))/(2)
-2 +- 2 sqrt (167)/(2)
common denominator of 2
-1 sqrt(167)/(2)
Would you help me understand where I went wrong and how to do it right?
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
Sign Error:
(-168)\ =\ 4\ -\ (-672)\ =\ 4\ +\ 672\ =\ 676\ =\ 26^2)
So it is a perfect square after all.
John
My calculator said it, I believe it, that settles it
RELATED QUESTIONS
Given that x^2+5x-14 is a factor of x^4-2x^3-37x^2+kx-168, evaluate the sum of the four... (answered by ikleyn)
Given that x^2+5x-14 is a factor of x^4-2x^3-37x^2+kx-168, evaluate the sum of the four... (answered by ikleyn)
[40/(x-2)] - 1 = [42/(x+2)]
Solve for x:
TRIED: and got -x^2 - 2x + 168 = 0 ; but this... (answered by user_dude2008,checkley77)
2x(x-5)=168 (answered by checkley79)
7* 2 squared-168 squared (answered by Alan3354)
Round the square roots to the nearest hundredth.
1.) sqrt of 320
2.) sqrt of... (answered by Alan3354)
I have a Final exam tommorow please help. Question: This width of a rectangle is 2cm less (answered by checkley71)
Please help and show me if I am doing this right! I have to solve an quadratic formula:... (answered by Alan3354,bucky)
factor by grouping:
4x^2 + 28x + 24x -... (answered by checkley77)
