Answer:
Step-by-step explanation:
Begin by combining like terms and then factoring. Combining like terms will give you
[tex]10p^2-17p-20=0[/tex] Using the "old-fashioned" way of factoring, the a times c method, our a = 10, b = -17 and c = -20.
a * c = 10(-20) = -200 and now we need the factors of 200 (don't worry about the negative) that combine to give us that middle term, -17p (here is where the negative matters). The factors of 200 are:
1. 200; 2, 100; 4. 50; 5, 40; 8, 25; 10, 20
The combination of those numbers that can be manipulated to give us a -17p is the 8, 25 as long as we say that the 25 is negative and the 8 is positive. Rewrite the original polynomial to reflect those factors:
[tex]10p^2-25p+8p-20=0[/tex] and then factor by grouping:
[tex](10p^2-25p)+(8p-20)=0[/tex] and factor out from each set of parenthesis what is common:
[tex]5p(2p-5)+4(2p-5)=0[/tex] again factor out what is common:
(2p - 5)(5p+ 4) = 0. These are the factors; therefore the solutions are
2p - 5 = 0 so
2p = 5 and
p = 5/2 and
5p + 4 = 0 and
5p = -4 so
p = -4/5
