1.If f(x) = 3x^2 + 5x, then find the value of x such that f(x) = 2

a) -2 b) -2/3 c) 0 d) 1/3 e)-2

My work:

2 = 3x^2+5x

0 = 3x^2+5x-2

(Input in graphing calculator, Then find the zeros)

I got -2 and 1/3

But the answer is "d". I'm confused.

2.Solve:3t^2 + 5t - 12 = 0. How do you solve this algebraically (without using a graphing calculator)? I'm clueless, so I can't show work.

Answer:t = -3 or 4/3

Can somebody help me out with these questions?

AlphaRock

I have a third one:

3. If (m, -2) is on a circle with center (-2,2) and a radius 9. Find the value of m.

My work:

(x+2)^2 + (-2-2)^2 = 9^2

(x+2)^2 + (-4)^2 = 81.

x^2 + 4x + 4 + 16 = 81.

x^2 + 4x + 20 -20 = 81 - 20

x^2 + 4x = 61.

x^2 + 4x - 64 = 0

Use graphing calculator...

x = 6.25

x = -10.25

REAL ANSWER: -2 +/- sqrt(65)

Can somebody show me what I can do to make this right?