Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

trative-math 
//×6418b49dfbc9d0c :quadratic-quations-part2/x6418b49dfbc9d0c9:apply-quadratio-formula-part2...
All Bookmarks
Khan Academy
Donate \square
nicolel3754
Tori and Gavin were trying to solve the equation:

(x+1)^(2)-3=13
Tori said, "I'Il add 3 to both sides of the equation and solve using square roots."
Gavin said, "I'll multiply 
(x+1)^(2) and rewrite the equation as 
x^(2)+2x+1-3=13. Then I'll subtract 13 from both sides, combine like terms, and solve using the quadratic formula with 
a=1,b=2, and 
c=-15."
Whose solution strategy would work?
Choose 1 answer:
(A) Only Tori's
(8) Only Gavin's
(c) Both

trative-math /×6418 b49dfbc9 d0c / \times 6418 \mathrm{~b} 49 \mathrm{df} b \mathrm{c} 9 \mathrm{~d} 0 \mathrm{c} :quadratic-quations-part22/x64186418b4949dfbc99d00c99:apply-quadratio-formula-part22...\newlineAll Bookmarks\newlineKhan Academy\newlineDonate \square\newlinenicolel37543754\newlineTori and Gavin were trying to solve the equation:\newline(x+1)23=13 (x+1)^{2}-3=13 \newlineTori said,

Full solution

Q. trative-math /×6418 b49dfbc9 d0c / \times 6418 \mathrm{~b} 49 \mathrm{df} b \mathrm{c} 9 \mathrm{~d} 0 \mathrm{c} :quadratic-quations-part22/x64186418b4949dfbc99d00c99:apply-quadratio-formula-part22...\newlineAll Bookmarks\newlineKhan Academy\newlineDonate \square\newlinenicolel37543754\newlineTori and Gavin were trying to solve the equation:\newline(x+1)23=13 (x+1)^{2}-3=13 \newlineTori said,
  1. Start with Tori's method: Start with Tori's method.\newlineEquation: (x+1)23=13(x+1)^2 - 3 = 13\newlineAdd 33 to both sides: (x+1)23+3=13+3(x+1)^2 - 3 + 3 = 13 + 3\newlineSimplify: (x+1)2=16(x+1)^2 = 16
  2. Solve using square roots: Solve using square roots.\newlineTake the square root of both sides: x+1=±16x+1 = \pm \sqrt{16}\newlineSimplify: x+1=±4x+1 = \pm 4
  3. Solve for x: Solve for xx.\newlineCase 11: x+1=4x+1 = 4\newlineSubtract 11 from both sides: x=3x = 3\newlineCase 22: x+1=4x+1 = -4\newlineSubtract 11 from both sides: x=5x = -5
  4. Check Gavin's method: Check Gavin's method.\newlineRewrite the equation: (x+1)23=13(x+1)^2 - 3 = 13\newlineExpand: x2+2x+13=13x^2 + 2x + 1 - 3 = 13\newlineSimplify: x2+2x2=13x^2 + 2x - 2 = 13\newlineSubtract 1313 from both sides: x2+2x213=0x^2 + 2x - 2 - 13 = 0\newlineCombine like terms: x2+2x15=0x^2 + 2x - 15 = 0
  5. Solve using the quadratic formula: Solve using the quadratic formula.\newlineQuadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\newlineHere, a=1a = 1, b=2b = 2, c=15c = -15\newlineCalculate discriminant: b24ac=224(1)(15)=4+60=64b^2 - 4ac = 2^2 - 4(1)(-15) = 4 + 60 = 64
  6. Continue solving: Continue solving.\newlineCalculate roots: x=2±642(1)=2±82x = \frac{-2 \pm \sqrt{64}}{2(1)} = \frac{-2 \pm 8}{2}\newlineCase 11: x=2+82=62=3x = \frac{-2 + 8}{2} = \frac{6}{2} = 3\newlineCase 22: x=282=102=5x = \frac{-2 - 8}{2} = \frac{-10}{2} = -5
  7. Conclusion: Conclusion.\newlineBoth Tori and Gavin's methods give the same solutions: x=3x = 3 and x=5x = -5

More problems from Compare linear and exponential growth