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Please help me with this problem

please show steps so i know for next time

Please help me with this problem please show steps so i know for next time-example-1
User Imani
by
7.3k points

1 Answer

6 votes

Answer: 2/3, -4/3

=========================================================

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
a\text{x}^2 + b\text{x} + c = 0

We have a = 9, b = 6, and c = -8

Those values lead to...


\text{x} = (-b\pm√(b^2-4ac))/(2a)\\\\\text{x} = (-6\pm√((6)^2-4(9)(-8)))/(2(9))\\\\\text{x} = (-6\pm√(324))/(18)\\\\\text{x} = (-6\pm18)/(18)\\\\\text{x} = (-6+18)/(18) \ \text{ or } \ \text{x} = (-6-18)/(18)\\\\\text{x} = (12)/(18) \ \text{ or } \ \text{x} = (-24)/(18)\\\\\boldsymbol{\text{x} = (2)/(3) \ \text{ or } \ \text{x} = -(4)/(3)}\\\\

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.
User Emremrah
by
6.8k points