solve let f(x)=-2x^2+9x+3. find f(-4)?

it's not exactly difficult

learn by doing

f ( - 4 ) = - 2 ( 16 ) - 36 + 3

f ( - 4 ) = - 32 - 36 + 3

f ( - 4 ) = - 68 + 3

f ( - 4 ) = - 65

-2(-4)^2-36+3
-32-36+3
-32-33
-65

f(x) = -2x^2 + 9x + 3
f(-4) = -2(-4)^2 + 9(-4) + 3
f(-4) = -2(16) + (-36) + 3
f(-4) = -32 - 36 + 3
f(-4) = -65

for this kind of question just plug the value into the equation. instead x they want -4,
so wherever you see x just put -4!
f(x) = -2x^2 + 9x +3

f(-4)=-2(-4)^2+9(-4)+3
= (-2).(16) +(-36) + 3 (here (-4)^2=(-4)x(-4)=+16)
= (-32) +(-36) +3
= (-68) + 3
= -65

f(x)=-2x^2+9x+3. find f(-4)?
substitute x with -4
f(x)=-2x^2+9x+3.
f(-4)=-2(-4^2)+9(-4)+3
.... = -2 (16) - 36 + 3
... = -32 -36 +3
.... = - 65

f(x) is the same thing as y, so this is a bit confusing...

y= 8^2 + -36 + 3
y= 64-36+3
y=31

No idea if that is right, but try it out.
Also, try the quadratic formula:)

f(x)= -2x^2+9x+3. find f(-4)
f(-4)= -2(-4)^2+9(-4)+3
f(-4)=-32-36+3
f(-4)=-68+3
f(-4)=-65

just apply -4 to x, in the original equation.. so
f(-4)= -2(-4)^2+9(-4)+3
=-2(16)-36+3
=-32-36+3
=-65

yep, pretty sure -65 is the answer! :D hope it helped

Just plug -4 into the equation where the x's are and solve.

f(x) = -2x^2 + 9x + 3

f(-4) = -2(-4)^2 + 9(-4) + 3

= -2(16) + (-36) + 3

= -32 - 36 + 3

= -65