x^2 = 11 - 4x , How do you answer this is in the quadratic formula?

Question

Need Help!!

Answer 1

Hi,

First, rewrite the quadratic equation in standard form. x²+4x -11=0 (Bring all terms to one side of the equal sign.)

Then, identify

a=1

b=4 and 

c=-11

 

Now use the quadratic formula to solve:

x= -4 ±√4²-4·1·(-11)

              2(1)

x=-4±√60

          2

x=-4±2√15

      2     2

x = -2±√15

The solution is {-2+√15, -2-√15}

Answer 2

You must first rearrange the equation into the standard form of 0=ax²+bx+c which would give

 

0=x²+4x-11 with coefficients: a=1, b=4, and c=-11.

 

Then you would need to plug a, b, and c into the quadratic formula:

 

x = -b±√(b²-4*a*c)           -->      x = -4±√(4²-4*1*-11)

             2a                                                  2*1

 

Finally, solve the equation algebraically for x.

 

x = -4±√(16+44)

              2

 

x = -4±√60

           2

 

x = -4±2√15

            2

 

x = -2±√15