Answer: 2/3, -4/3
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Step-by-step explanation:
You could use the AC method to factor this, but the quadratic formula is the most efficient route in my opinion. This will avoid any guess-and-check.
Compare the original equation to the form

We have a = 9, b = 6, and c = -8
Those values lead to...

Side notes:
- 2/3 = 0.667 approximately
- -4/3 = 1.333 approximately
- Since your teacher did not give rounding instructions, I'll assume s/he wants the fraction form of each x value (rather than the decimal form). Be sure to follow all instructions given, and ask for clarification if need.
- To confirm the solutions, replace every copy of x with either 2/3 or -4/3 (pick one value only). Simplifying the left hand side should lead to 0. I'll let you check each answer.