Questions on Algebra: Quadratic Equation answered by real tutors!

Algebra ->  Algebra  -> Quadratic Equations and Parabolas -> Questions on Algebra: Quadratic Equation answered by real tutors!     (Log On)
Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebra Solved!™: algebra software that solves YOUR algebra homework problems with step-by-step help!

   

Question 151058: please help me solve this problem using the quadratic root formula: x^2-x+20=0: please help me solve this problem using the quadratic root formula: x^2-x+20=0
Answer by jim_thompson5910(9226) About Me  (Show Source):
You can put this solution on YOUR website!

x^2-x+20=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax^2+bx+c where a=1, b=-1, and c=20


Let's use the quadratic formula to solve for x


x = (-b +- sqrt( b^2-4ac ))/(2a) Start with the quadratic formula


x = (-(-1) +- sqrt( (-1)^2-4(1)(20) ))/(2(1)) Plug in a=1, b=-1, and c=20


x = (1 +- sqrt( (-1)^2-4(1)(20) ))/(2(1)) Negate -1 to get 1.


x = (1 +- sqrt( 1-4(1)(20) ))/(2(1)) Square -1 to get 1.


x = (1 +- sqrt( 1-80 ))/(2(1)) Multiply 4(1)(20) to get 80


x = (1 +- sqrt( -79 ))/(2(1)) Subtract 80 from 1 to get -79


x = (1 +- sqrt( -79 ))/(2) Multiply 2 and 1 to get 2.


x = (1 +- i*sqrt(79))/(2) Simplify the square root


x = (1+i*sqrt(79))/(2) or x = (1-i*sqrt(79))/(2) Break up the expression.


So our answers are x = (1+i*sqrt(79))/(2) or x = (1-i*sqrt(79))/(2)


which approximate to x=0.5+4.444*i or x=0.5-4.444*i