math problems?

3 ⤊

Given f(x) = 5x2 – 3x + 1, find f(–2).

A) 15 B) 27 C) –13 D) –25

2007-07-26 06:43:44 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

5x² - 3x + 1

5(-2)² - 3(- 2) + 1

5(4) - (- 6) + 1

20 + 6 + 1

26 + 1

27

- - - - - -s-

2007-07-26 06:56:55 · answer #1 · answered by SAMUEL D 7 · 2⤊ 0⤋

20 + 6 + 1 = 27 (B)

2007-07-26 13:48:56 · answer #2 · answered by John V 6 · 1⤊ 0⤋

f(-2) = 5(-2)(2) - 3(-2) + 1
f(-2) = -20 + 6 + 1
f(-2) = -13

C. â¥

John V is wrong because a positive (5) times a negative (-2) is a negative (-10). So, when you multiple a negative (-10) by a positive (2) you still get a negative (-20).

2007-07-26 13:52:14 · answer #3 · answered by Anonymous · 0⤊ 1⤋