## Algebra 1

Given the polynomial $k^{2}$ -18k - 63 *** We break of the middle term into two factors that add to give -18 and multiply to give -63. The two numbers are -21 and +3. $k^{2}$ -21k +3k - 63 We take the GCD of the first two and the GDC of the last two terms. k(k-21) +3(k-21) We take (k-21) and factor it out which gives us. (k-21)(k+3)