If some one could me with these three questions i will be !me my teacher didn’t walk us through this at all

17) replace the given number for "x" and evaluate

a) x² + 2x + 1   ; when x = 3

  3² + 2(3) + 1

= 9 + 6 + 1

= 16

b) x² + 2x + 1   ; when x = -4

  (-4)² + 2(-4) + 1

= 16 - 8 + 1

= 9

c) x² + 2x + 1   ; when x = 3

  (-22.872)² + 2(-22.872) + 1

= 523.128384 - 45.744 + 1

= 478.384384

18) The dependent variable is affected by the other variable and is the "output"   The independent variable is the input.

a) y = 3x - 5;    "x" is the independent variable

b) the time of day is the independent variable  (you would input the time of day to calculate the temperature).

19) Let the x-axis represent the length of the lumber cut off and the y-axis represent the length of the lumber remaining.

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it