Let f (x) satisfy that f (f (x)) equals 4x minus 1 to find f (x)

Let f (x) satisfy that f (f (x)) equals 4x minus 1 to find f (x)

Let f (x) = ax + B be solved by undetermined coefficient method

If f (x) is a decreasing function and f (f (x)) = 4x-2, then f (x)=
What does FX stand for,

F (x) is a function of X It's equivalent to y
Let f (x) = KX + B
f(f(x))=k(kx+b)+b=4x-2
The solution is k = - 2, B = 2 / 3 or K = 2, B = - 2
And because of the decreasing function, K is negative, and the latter is negative

F (x) = x ^ 2-m / 4x + 20, when x belongs to [- 2, + &), it is an increasing function, when x belongs to [- &, - 2), it is a decreasing function, then f (- 1) is equal to
Write down the process, thank you

If we have conditions, we can know that the symmetry axis of the parabola corresponding to f (x) is x = (M / 4) / 2, that is, x = m / 8, and if we have conditions, we can know that the symmetry axis is x = - 2
So m / 8 = - 2, M = - 16
f（x）=x^2+4x+20
f(-1)=(-1)^2-4+20
=17

Given that f (x) is equal to the square of 4x minus 3, then f (1 / 2) is equal to what,

F (1 / 2) is the value of x = 1 / 2
So f (1 / 2) = 4 * 1 / 4-3 = - 2

If the square of function f (x) = 4x - MX + 5 is an increasing function on [- 2, positive infinity) and a decreasing function on (negative infinity, - 2), then f (1) is equal to
A、-7
B、1
C、17
D、25
2. Given a = log3, then lo3 8-2log3 6 is expressed as
A、a-2
B、5a-2
C. The square of 3A - (a + a)
D. The square of 3a-a-1
3. Let the complete set be r, a = (x | 3 less than or equal to X | 7), B = (x | 2 less than x | 10), C = (x | 0 less than x-a less than 3)
If the set formed by the common parts of B and C is not an empty set, find the range of real number a.

(1)
The function f (x) = 4x & # 178; - MX + 5 is an increasing function on [- 2, + ∞) and a decreasing function on (- ∞, - 2)
The axis of symmetry is x = - 2
Axis of symmetry equation x = - B / (2a) = m / 8 = - 2
∴m=-16
f（x）=4x²+16x+5
f(1)=4+16+5=25
Choose D
(2)
log3 8-2log3 6
=log3 2³-2log3 (2*3)
=3log3 2-2(log3 2+log3 3)
=3log3 2-2log3 2-2log3 3
=log3 2-2
=a-2
Choose a
（3）
A={x|3

When m is a value, the solution of the equation m (3x-1) = 4x + m-2 is equal to o
Can you answer it directly

The solution of the equation is equal to 0, that is, x = 0
m(3x-1)=4x+m-2
-m=m-2
2m=2
m=1

Given that the solution of the equation m (3x-1) = 4x + m-2 about X is equal to 0, then M (3x-1) = 4x + m-2=_________

That is, x = 0
Substituting
-m=m-2
2m=2
m=1

Solving inequality (x ^ 2 + 4x + 3) (x ^ 2 + 6x + 8) > 120
I'll finish at eight o'clock tomorrow morning, during which time I can,

(x+3)(x+1)(x+2)(x+4)>120
[(x+1)(x+4)][(x+2)(x+3)]>120
[(x^2+5x)+4][(x^2+5x)+6]>120
(x^2+5x)^2+10(x^2+5x)+24-120>0
(x^2+5x)^2+10(x^2+5x)-96>0
(x^2+5x+16)(x^2+5x-6)>0
x^2+5x+16=(x+5/2)^2+39/4>0
So x ^ 2 + 5x-6 > 0
(x+6)(x-1)>0
x>1.x

The solution ratio 3x-10:2x = 0.75:1.5 4x + 10:3x-30 = 14:3

3X-2X/10=1.5/0.75
3X-X/5=2
3-1/5=2/X
X=10

4x-30 / 3x-30 = one third

4x-30 / 3x-30 = one third
3（3x-30）=4x-30
9x-90=4x-30
9x-4x=90-30
5x=60
x=12
Click comment in the upper right corner, and then you can select satisfied, the problem has been solved perfectly