If f(x) = 2x2 - x, how do you find f(-3)? This doesnt make any sense. please help me!
O OMB26 New member Joined Mar 15, 2010 Messages 1 Mar 15, 2010 #1 If f(x) = 2x2 - x, how do you find f(-3)? This doesnt make any sense. please help me!
M Mrspi Senior Member Joined Dec 17, 2005 Messages 2,128 Mar 15, 2010 #2 OMB26 said: If f(x) = 2x2 - x, how do you find f(-3)? This doesnt make any sense. please help me! Click to expand... f(x) = 2x^2 - x tells us that for any "x", the function f(x) means to take x, square it, multiply the result by 2, and then subtract x. So, for example, f(5) tells us to take 5, square it, multiply the result by 2, and then subtract 5: f(5) = 2*(5)^2 - 5 f(5) = 2*25 - 5 f(5) = 50 - 5 f(5) = 45 Can you repeat this process when you use -3 for x? f(-3) = 2*(-3)^2 - (-3) Do the arithmetic.
OMB26 said: If f(x) = 2x2 - x, how do you find f(-3)? This doesnt make any sense. please help me! Click to expand... f(x) = 2x^2 - x tells us that for any "x", the function f(x) means to take x, square it, multiply the result by 2, and then subtract x. So, for example, f(5) tells us to take 5, square it, multiply the result by 2, and then subtract 5: f(5) = 2*(5)^2 - 5 f(5) = 2*25 - 5 f(5) = 50 - 5 f(5) = 45 Can you repeat this process when you use -3 for x? f(-3) = 2*(-3)^2 - (-3) Do the arithmetic.
