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.

take it another