Respuesta :
Answer:
Q13 - A. ±1, ±2, ±3, ±4, ±6, ±8, ±12, ±24
Q14 - A. [tex]7x+6+4x^{2}[/tex]
Q15 - D. [tex]f(x)=x^{3}-3x^{2}-28x+60[/tex]
Q16 - D. 20.9 ft
Q17 - A. x ≥ -9, x ≠ -3, x ≠ 7
Q18 - B. 2π
Step-by-step explanation:
Question 13:
Rational Zeros Theorem states that 'If p(x) is a polynomial with integer coefficients and if [tex]\frac{p}{q}[/tex] is a zero of p(x) = 0. Then, p is a factor of the constant term of p(x) and q is a factor of the leading coefficient of p(x)'.
Let, [tex]\frac{p}{q}[/tex] is a zero of [tex]x^3-7x^2+9x-24=0[/tex]. Then, p is a factor of -24 and q is a factor of 1.
Thus, possible values of p = ±1, ±2, ±3, ±4, ±6, ±8, ±12, ±24 and q = ±1
This gives, possible values of [tex]\frac{p}{q}[/tex] are ±1, ±2, ±3, ±4, ±6, ±8, ±12, ±24.
Question 14:
We have, f(x) = 7x + 6 and g(x) = [tex]4x^{2}[/tex]
Then, (f+g)(x) = f(x) + g(x) = 7x + 6 + [tex]4x^{2}[/tex]
So, (f+g)(x) = [tex]7x+6+4x^{2}[/tex]
Question 15:
Zeros of the function are given by 6, -5, 2.
Thus, the factored form will be [tex](x-6)(x+5)(x-2)=0[/tex]
i.e. [tex](x^{2}+5x-6x-30)(x-2)=0[/tex]
i.e. [tex](x^{2}-x-30)(x-2)=0[/tex]
i.e. [tex](x^{3}-2x^{2}-x^{2}+2x-30x+60=0[/tex]
i.e. [tex]x^{3}-3x^{2}-28x+60=0[/tex]
So, the cubic function is [tex]f(x)=x^{3}-3x^{2}-28x+60[/tex].
Question 16:
Let, the length of the ramp = x feet.
The horizontal length of the ramp = 20 feet
The vertical length of the ramp = 6 feet.
Using Pythagoras Theorem, we have,
[tex]x^{2}=20^{2}+6^{2}[/tex]
i.e. [tex]x^{2}=400+36[/tex]
i.e. [tex]x^{2}=436[/tex]
i.e. [tex]x=\pm 20.9[/tex]
Since, the length of the ramp cannot be negative.
Hence, the length of the ramp is 20.9 feet.
Question 17:
We have the function, [tex]f(x)=\frac{\sqrt{x+9}}{(x+3)(x-7)}[/tex]
As the quantities in square roots are always positive, then x+9≥0 i.e. x≥-9.
Also, the function is not defined at x = -3 and x = 7.
Thus, the domain is x ≥ -9 and x ≠ -3, x ≠ 7.
Question 18:
We have the function y = -3 cosx
As, there will be no affect on the period by the quantity -3 and the period of the cosine function is 2π.
Thus, period of y = -3 cosx is 2π.