The three techniques are factoring, factor by grouping, and completing the square.
Factoring:
- Step 1) Create a factor chart for all factor pairs of c
- A factor pair is just two numbers that multiply and give you 'C'
- Step 2) Out of all of the factor pairs from step 1, look for the pair (if it exists) that add up to b
- Note: If the pair does not exist, you must either complete the square or use the quadratic formula .
- Step 3) Insert the pair you found in step 2 into twobinomals
- Step 4) Solve each binomial for zero to get the solutions of the quadratic equation.
- Step 1) Determine the product of AC (the coefficientsin the quadratic equation Ax^2 + Bx + C = 0)
- Step 2) Determine what factors of a⋅c sums up to b.
- Step 3) "ungroup" the middle term to become the sum of the factors found in step 2
- Step 4) group the pairs.
The process for finding the last term of a perfect square trinomial.
However, in this case, 3x^2 + x - 2 = 0 is not a perfect square trinomial, so we cannot use "Completing the square" as a method of solving the quadratic equation.
I'm going to be honest: Using the quadratic equation to solve these equations is much, MUCH easier than these three other methods. It may seem more time consuming, but it's a method that you KNOW will work for sure. So let's go ahead and do that:
x = {-1 ± √(1)^2 - 4(3)(-2)}/2(3)
= (-1 ± √25)/6
= (-1 ± 5)/6
Your two answers will be: (-1 + 5)/6 and (-1 - 5)/6, which simplifies to 2/3 and -1.