How do you solve the quadratic 3r2−5=−10 using any method? Precalculus Linear and Quadratic Functions Completing the Square 1 Answer Shell Dec 2, 2016 r=±√153i Explanation: 3r2−5=−10 a2a+5aa2a+5aaaAdd 5 to both sides 3r2=−5 3r23=−53aaaDivide both sides by 3 r2=−53 √r2=√−53aaaSquare root both sides r=±i√53aaThe negative inside the square root comes out as i. r=±i√53⋅√33aaaRationalize the denominator r=±i√153=±√153i Answer link Related questions What does completing the square mean? How do I complete the square? Does completing the square always work? Is completing the square always the best method? Do I need to complete the square if f(x)=x2−6x+9? How do I complete the square if f(x)=x2+4x−9? How do I complete the square if the coefficient of x2 is not 1? How do I complete the square if f(x)=3x2+12x−9? If I know the quadratic formula, why must I also know how to complete the square? How do I use completing the square to describe the graph of f(x)=30−12x−x2? See all questions in Completing the Square Impact of this question 1948 views around the world You can reuse this answer Creative Commons License