If f(x)=-x^2+4x+2, for what value(s) of x is f(x)=4
2006-11-20 02:45:56 · 9 answers · asked by HeArtBr0Ken... 2 in Science & Mathematics ➔ Mathematics
no clue!
2006-11-20 02:55:36 · answer #1 · answered by dodd319 4 · 0⤊ 1⤋
Put x^2+4x+2=4
this gives x= -2+root 6
-2-root 6
2006-11-20 10:52:27 · answer #2 · answered by promy 1 · 0⤊ 0⤋
This is too simple,
You know, f(x) should be equivalent to 4:
f(x)=4
Putting f(x)'s condition to the equation above:
-x^2 + 4x + 2 = 4
Adding (-4) to both sides of the equation:
-x^2 + 4x -2 = 0
By solving this equation for x, you will find the answer(s).
2006-11-20 10:54:56 · answer #3 · answered by Babax 3 · 0⤊ 0⤋
using the pemdas (parentesis, exponents, multication*, division*, add* and subtract*)
*going left to right in the problem which ever operation is first
-x^2+4x+2 (x = 4)
-4^2+4(4)+2
-16+16+2
-34
thats what i get but i could be wrong
2006-11-20 11:04:33 · answer #4 · answered by jamz 5 · 0⤊ 0⤋
f(x) = 4
-x^2+4x+2 = 4
-x^2+4x+2 - 4 = 0
-x^2+4x- 2 = 0
Use ABC....
x = 3,414 AND x = 0,586
2006-11-20 11:00:12 · answer #5 · answered by Anonymous · 0⤊ 0⤋
f(x) = x^2+4x+2 = 4
if (x^2+4x+4) = 6 ( by adding 2 on both sides to make it square)
if(x+2)^2 = 6
if x +2 = +/- sqrt(6)
if x= - 2+ sqrt(6) or -2- sqrt(6)
2006-11-20 10:54:32 · answer #6 · answered by Mein Hoon Na 7 · 0⤊ 0⤋
put f(x)= 4
4= x^2+4x+2
x^2+4x=2
x^2+4x-2=0
simplify!!
2006-11-20 10:51:45 · answer #7 · answered by Ankit B 4 · 0⤊ 0⤋
x^2+4x+2=4 => x^2+4x-2=0
delta=16+8=24=(2sqrt(6))^2
x1=(-4-2sqrt(6))/2=-2-sqrt(6)
x2=(-4+2sqrt(6))/2=-2+sqrt(6)
2006-11-20 10:53:50 · answer #8 · answered by Iulia-Diana 2 · 0⤊ 0⤋
i used to know how to do that stuff
but i forgot over the summer haha
sorry
2006-11-20 10:47:41 · answer #9 · answered by samantha 2 · 0⤊ 1⤋