Q. Addison solves the equation below by first squaring both sides of the equation.2x−1=8−xWhat extraneous solution does Addison obtain?x=
Write Equation: Write down the original equation.2x−1=8−x
Square Both Sides: Square both sides of the equation to eliminate the square root.(2x−1)2=(8−x)2
Perform Squaring: Perform the squaring on both sides.(2x−1)(2x−1)=8−x
Expand Left Side: Expand the left side of the equation using the FOIL method (First, Outer, Inner, Last).4x2−2x−2x+1=8−x
Combine Like Terms: Combine like terms on the left side of the equation.4x2−4x+1=8−x
Add x to Both Sides: Add x to both sides of the equation to bring all x terms to one side.4x2−4x+x+1=8
Subtract 8: Combine like terms on the left side of the equation.4x2−3x+1=8
Factor or Use Quadratic Formula: Subtract 8 from both sides of the equation to set the equation to zero.4x2−3x+1−8=0
Calculate Discriminant: Combine like terms on the left side of the equation. 4x2−3x−7=0
Find Solutions: Factor the quadratic equation, if possible, or use the quadratic formula to find the solutions for x. The quadratic formula is x=2a−b±b2−4ac, where a=4, b=−3, and c=−7.
Check Solutions: Calculate the discriminant (b2−4ac) to determine the nature of the roots.Discriminant = (−3)2−4(4)(−7)Discriminant = 9+112Discriminant = 121
Extraneous Solution: Since the discriminant is positive, there are two real solutions. Calculate the solutions using the quadratic formula.x=83±121x=83±11
Extraneous Solution: Since the discriminant is positive, there are two real solutions. Calculate the solutions using the quadratic formula.x=83±121x=83±11Find the two solutions.x=8(3+11) or x=8(3−11)x=814 or x=8−8x=1.75 or x=−1
Extraneous Solution: Since the discriminant is positive, there are two real solutions. Calculate the solutions using the quadratic formula.x=83±121x=83±11 Find the two solutions.x=8(3+11) or x=8(3−11)x=814 or x=8−8x=1.75 or x=−1 Check both solutions in the original equation to see if any of them is extraneous.For x=1.75:2(1.75)−1=8−1.75x=83±110x=83±111 (True)For x=−1:x=83±113x=83±114x=83±115 (False)
Extraneous Solution: Since the discriminant is positive, there are two real solutions. Calculate the solutions using the quadratic formula.x=83±121x=83±11Find the two solutions.x=83+11 or x=83−11x=814 or x=8−8x=1.75 or x=−1Check both solutions in the original equation to see if any of them is extraneous.For x=1.75:2(1.75)−1=8−1.75x=83±110x=83±111 (True)For x=−1:x=83±113x=83±114x=83±115 (False)The solution x=−1 does not satisfy the original equation, so it is the extraneous solution.x=−1
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