Q. Avery solves the equation below by first squaring both sides of the equation.z2+8=1−2zWhat extraneous solution does Avery obtain?z=
Rephrasing the problem: First, let's rephrase the "What extraneous solution does Avery obtain when solving the equation involving a square root by squaring both sides?"
Squaring both sides: Avery starts with the equation z2+8=1−2z. To eliminate the square root, Avery squares both sides of the equation.(\sqrt{z^\(2\) + \(8\)})^\(2 = (1 - 2z)^2
Expanding the equation: After squaring both sides, the equation becomes: z2+8=(1−2z)2
Rearranging the equation: Next, Avery expands the right side of the equation:z2+8=12−2(1)(2z)+(2z)2z2+8=1−4z+4z2
Combining like terms: Now, Avery rearranges the equation to set it to zero:0=4z2−4z+1−z2−8
Simplifying the square root: Avery uses the quadratic formula to solve for z: z=2⋅3−(−4)±(−4)2−4(3)(−7) z=64±16+84 z=64±100
Finding the solutions: Avery simplifies the square root and continues solving:z=64±10This gives two solutions: z=6(4+10) and z=6(4−10)
Checking the solutions: Avery finds the two solutions:z = 614 and z = 6−6z = 37 and z = −1
Checking the solutions: Avery finds the two solutions:z=614 and z=6−6z=37 and z=−1Avery checks both solutions by substituting them back into the original equation:For z=37:(37)2+8=1−2(37)949+972=1−3149121=1−314311=1−314311=−311This is not true, so z=37 is an extraneous solution.
Checking the solutions: Avery finds the two solutions:z=614 and z=6−6z=37 and z=−1Avery checks both solutions by substituting them back into the original equation:For z=37:(37)2+8=1−2(37)949+972=1−3149121=1−314311=1−314311=−311This is not true, so z=37 is an extraneous solution.For z=−1:z=6−62z=6−63z=6−64z=6−65This is true, so z=−1 is a valid solution.
More problems from Evaluate recursive formulas for sequences