Q. Solve for all values of x.x−4x+3=x−5Answer: x=
Cross-multiply fractions: Cross-multiply to eliminate the fractions. (x+3)⋅x=(−5)⋅(x−4)
Distribute equation sides: Distribute both sides of the equation. x2+3x=−5x+20
Move terms set zero: Move all terms to one side to set the equation to zero. x2+3x+5x−20=0
Combine like terms: Combine like terms. x2+8x−20=0
Factor quadratic equation: Factor the quadratic equation, if possible.However, the quadratic x2+8x−20 does not factor nicely. We will use the quadratic formula instead.
Apply quadratic formula: Apply the quadratic formula.x=2a−b±b2−4ac, where a=1, b=8, and c=−20.
Calculate discriminant: Calculate the discriminant (b2−4ac). Discriminant = (8)2−4(1)(−20)=64+80=144
Calculate solutions: Calculate the two solutions using the quadratic formula.x=2(1)−8±144x=2−8±12
Solve for x values: Solve for the two values of x.x=(−8+12)/2=4/2=2x=(−8−12)/2=−20/2=−10
Check extraneous solutions: Check for extraneous solutions by plugging the values back into the original equation.For x=2:(2+3)/(2−4)=(−5)/25/(−2)=(−5)/2−5/2=−5/2 (Valid solution)For x=−10:(−10+3)/(−10−4)=(−5)/(−10)−7/(−14)=1/21/2=1/2 (Valid solution)Both solutions are valid and do not create any undefined conditions in the original equation.
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