Question 120419

a)


Let's evaluate {{{f(2)}}}



{{{f(x)=2t^2-4t-1}}} Start with the given function.



{{{f(2)=2(2)^2-4(2)-1}}} Plug in {{{t=2}}}. In other words, replace each t with 2.



{{{f(2)=2(4)-4(2)-1}}} Evaluate {{{(2)^2}}} to get 4.



{{{f(2)=+8-4(2)-1}}} Multiply 2 and 4 to get  8



{{{f(2)=+8-8-1}}} Multiply -4 and 2 to get  -8



{{{f(2)=-1}}} Now combine like terms






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b)



Let's evaluate {{{f(-1)}}}



{{{f(x)=2t^2-4t-1}}} Start with the given function.



{{{f(-1)=2(-1)^2-4(-1)-1}}} Plug in {{{t=-1}}}. In other words, replace each t with -1.



{{{f(-1)=2(1)-4(-1)-1}}} Evaluate {{{(-1)^2}}} to get 1.



{{{f(-1)=+2-4(-1)-1}}} Multiply 2 and 1 to get  2



{{{f(-1)=+2+4-1}}} Multiply -4 and -1 to get  4



{{{f(-1)=5}}} Now combine like terms