Education.com
Try
Brainzy
Try
Plus

Tip #41 to Get a Top SAT Math Score (page 3)

By McGraw-Hill Professional
Updated on Sep 10, 2011

1. B Nice function review! f(–p) means plug –p in for x. So f(–p) =–2(–p)3 =–2(–p3) = 2p3. Careless error buster: Remember that the 2 is not inside the parentheses and does not get cubed with the p.
2. A Plug in m =–1 and simplify. m(2x2 – 2) = –1(2x2 – 2) =–2x2 + 2. Careless error buster: Remember to distribute the negative sign!
3. D Plug x = 3 into the equation to get not a – 15. Careless error buster: Remember to also divide the 15 by 3.
4. E Plug 2p in for m and then FOIL (2p + 4)2. You can use the algebra trick for FOILing a binomial if you know it, and if you don't, no sweat, just do it out: (2p + 4)2 = (2p + 4) (2p + 4) = 4p2 + 8p + 8p + 16 = 4p2 + 16p + 16. Skill 42 preview: When you FOIL, remember the middle term!
5. A Another function review, this is a good day. This question is similar to number 3 above, but more involved. Plug –2p in for x: f(–2p) = –2p (2(–2p)2 – 2) =–2p(2(4p2) – 2) = –2p(8p2 – 2) =–16p3 + 4p. Careless error buster: Remember to distribute the negative sign!
6. 360. Serious functions review! Plug m in for x and 27 in for the result: 27 = 3m, so m = 9. Next, plug –2m, which we now know equals –18, into the f function: –18(–18 – 2) = –18(–20) =+360. Skill 42 preview: Finish the question, don't stop with m = 9. Remember to ask, "Did I finish the question?"

Go to: Tip #42