Question 1090824
{{{f(x)= -2x^2+4x}}}

choose values for {{{x}}}, calculate {{{f(x)}}} or {{{y}}} (it is same), and make table

{{{x}}}|{{{y}}}

{{{-2}}}|{{{-16}}} ->{{{f(-2)= -2(-2)^2+4(-2)=-2*4-8=-8-8=-16}}}

{{{-1}}}|{{{-6}}} ->{{{f(-1)= -2(-1)^2+4(-1)=-2*1-4=-2-4=-6}}}

{{{0}}}|{{{0}}} ->{{{f(0)= -2(0)^2+4(0)=0+0=0}}}

{{{1}}}|{{{2}}} ->{{{f(1)= -2(1)^2+4(1)=-2+4=2}}}

{{{2}}}|{{{0}}} ->{{{f(2)= -2(2)^2+4(2)=-2*4+8=-8+8=0}}}

{{{3}}}|{{{-6}}} ->{{{f(3)= -2(3)^2+4(3)=-2*9+12=-18+12=-6}}}

plot these points and draw a line:


{{{drawing( 600, 600, -10, 10, -20, 10,
circle(-2,-16,.13),circle(-1,-6,.13),circle(3,-6,.13),
circle(0,0,.13),circle(1,2,.13),circle(2,0,.13),
locate(-2,-16,p(-2,-16)),locate(-1,-6,p(-1,-6)),locate(3,-6,p(3,-6)),
locate(2,0.7,p(2,0)),locate(1,2,p(1,2)),locate(0,-0.3,p(0,0)),
 graph( 600, 600, -10, 10, -20, 10, -2x^2+4x)) }}}