the section iam doing is called "5-12 solving equations by factoring"
and i cant seem to get a reasonable answer to these problems
6c^2-72=11c
4x^3-12x^2+8x=0
2n^3-30n^2+100n=0
please show how you did it so i can learn
We want a pair of factors of (the coefficient of the term times the coefficient of the constant term) that add to -11:
1, -432 --> -431
2, -216 --> -214
3, -144 --> -141
etc.
At some point in the list we get to:
16, -27 --> -11
So we split the middle term: :
(You can verify that this is our factorization by multiplying it out.)
So either or .
Thus or .
You can apply the method above (split the -3x into -x - 2x and factor by grouping as in the above), but you can probably factor this by looking at it. Either way:
So x = 0, 1, or 2.
To factor the second term we need to find a pair of numbers that are factors of that add up to -15. I get -5 and -10:
Thus n = 0, 5, or 10.
-Dan