Question

3a^(2) - 21a + 30 factor completely. The answer is 3(a - 2)(a-5) but thats not what I keep getting. how do you get to the answer?

Answer 1

\[3 a^2-21 a+30=3\left(a^2-7 a+10\right)=3 (a-5) (a-2) \]

Answer 2

where does the -5 and the -2 come from in the equation?

Answer 3

quadratic formulas

Answer 4

http://www.purplemath.com/modules/factquad.htm