Q. Find one value of x that is a solution to the equation:(3x−2)2−4=9x−6x=
Write and simplify equation: Write down the given equation and simplify it if possible.(3x−2)2−4=9x−6
Expand squared term: Expand the squared term (3x−2)2.(3x−2)(3x−2)−4=9x2−6x−6x+4−4=9x2−12x9x2−12x=9x−6
Move terms to one side: Move all terms to one side to set the equation to zero.9x2−12x−9x+6=09x2−21x+6=0
Factor or use quadratic formula: Factor the quadratic equation if possible.Looking for two numbers that multiply to 9×6=54 and add up to −21 is difficult, and it seems that the quadratic does not factor nicely. We will use the quadratic formula instead.x=2a−b±b2−4acHere, a=9, b=−21, and c=6.
Apply quadratic formula: Apply the quadratic formula.x=2⋅9−(−21)±(−21)2−4⋅9⋅6x=1821±441−216x=1821±225
Simplify and solve for x: Simplify under the square root and solve for x.x=1821±15We have two possible solutions:x=18(21+15)x=1836x=2orx=18(21−15)x=186x=31
Check solutions in original equation: Check both solutions in the original equation.For x=2:(3(2)−2)2−4=9(2)−6(6−2)2−4=18−642−4=1216−4=1212=12
Discard incorrect solution: Since the solution x=31 does not satisfy the original equation, we discard it. The solution x=2 is the correct value that satisfies the equation.
More problems from Solve a quadratic equation by factoring