Write the quadratic function f(x) = 3(x + 1)(x – 7) in standard form. A)

f(x) = x2 – 18x – 21

B)

f(x) = 3x2 – 18x – 21

C)

f(x) = x2 – 6x – 7

D)

f(x) = 3x2 – 6x – 7

B

Step-by-step explanation:

Given

f(x) = 3(x + 1)(x - 7) ← expand the factors using FOIL

     = 3(x² - 6x - 7) ← distribute the parenthesis

      = 3x² - 18x - 21 → B

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

option a, c,d are correct.

step-by-step explanation:

from the given figure, it is given that z is equidistant from the sides of the triangle rst, then from triangle tzb and triangle szb, we have

tz=sz(given)

bz=zb(common)

therefore, by rhs rule,δtzb ≅δszb

by cpctc, sz≅tz

also, from δctz and δasz,

tz=sz(given)

∠tcz=∠saz(90°)

by rhs rule, δctz ≅ δasz, therefore by cpctc, ∠ctz≅∠asz

also,from δasz and δzsb,

zs=sz(common)

∠zbs=∠saz=90°

by rhs rule, δasz ≅δzsb, therefore, by cpctc, ∠asz≅∠zsb

hence, option a, c,d are correct.