maybe you can help me out...
two functions are given below.
f(x)=x2(x squared) + 2x -1
g(x)=5x + 3
find the values of x for which f(x)=g(x)
2007-02-04 01:45:28 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The roots are real and distinct.
x1=4.0
x2=-1.0
2007-02-04 02:04:14 · answer #1 · answered by Cool Sun 3 · 0⤊ 0⤋
You can do it this way:
Write down
f(x) = g(x)
Then write it again, but put in what f(x) and g(x) are.
x^2 + 2x -1 = 5x + 3
Add -5x -3 to each side
x^2 + 2x -1 -5x -3 = 5x + 3 -5x -3
Collect terms
x^2 -3x -4 = 0
Solve for x
r^2 = (-3)^2 - 4(1)(-4) = 9 +16 = 25
r = (+ or -) 5
x = [ -(-3) (+ or -) r ] / 2
Once you have the two values of x, be sure to check your work by calculating f(x) and g(x) for each value.
2007-02-04 09:53:24 · answer #2 · answered by morningfoxnorth 6 · 0⤊ 0⤋
well...
you set the two equations equal to each other so:
X2 (x squared) +2x-1=5x+3
Then simplify:
x2-3x-4=0
Then factor:
(x+1) (x-4)
x= -1 x=4
Then you plug in the two answers into the equation and c if they are equal...u then see that the answer is 4!
2007-02-04 09:55:29 · answer #3 · answered by Di 2 · 1⤊ 0⤋
If f(x) = g(x) then x²+2x-1 = 5x+3.
So x²-3x-4 = 0.
(x-4)(x+1) = 0
Now set each factor equal to 0 and solve:
x = -1 or x = 4.
2007-02-04 11:59:24 · answer #4 · answered by steiner1745 7 · 0⤊ 0⤋
x2 + 2x - 1 = 5x + 3
x2 - 3x - 4 = 0
Use the quadratic formula to find the 2 roots.
2007-02-04 09:50:56 · answer #5 · answered by Thomas K 6 · 0⤊ 0⤋