trative-math /×6418b49dfbc9d0c :quadratic-quations-part2/x6418b49dfbc9d0c9:apply-quadratio-formula-part2...All BookmarksKhan AcademyDonate \squarenicolel3754Tori and Gavin were trying to solve the equation:(x+1)2−3=13Tori said,
Q. trative-math /×6418b49dfbc9d0c :quadratic-quations-part2/x6418b49dfbc9d0c9:apply-quadratio-formula-part2...All BookmarksKhan AcademyDonate \squarenicolel3754Tori and Gavin were trying to solve the equation:(x+1)2−3=13Tori said,
Start with Tori's method: Start with Tori's method.Equation: (x+1)2−3=13Add 3 to both sides: (x+1)2−3+3=13+3Simplify: (x+1)2=16
Solve using square roots: Solve using square roots.Take the square root of both sides: x+1=±16Simplify: x+1=±4
Solve for x: Solve for x.Case 1: x+1=4Subtract 1 from both sides: x=3Case 2: x+1=−4Subtract 1 from both sides: x=−5
Check Gavin's method: Check Gavin's method.Rewrite the equation: (x+1)2−3=13Expand: x2+2x+1−3=13Simplify: x2+2x−2=13Subtract 13 from both sides: x2+2x−2−13=0Combine like terms: x2+2x−15=0
Solve using the quadratic formula: Solve using the quadratic formula.Quadratic formula: x=2a−b±b2−4acHere, a=1, b=2, c=−15Calculate discriminant: b2−4ac=22−4(1)(−15)=4+60=64