True or false: any value that is uknown or can change is a variable

For [tex]f(x) = 4x+1[/tex] and [tex]g(x) = x^{2} -5[/tex] find [tex](f[/tex] ° [tex]g)[/tex][tex](4)[/tex]

Me asap! what is the slope of this line? enter your answer in the box.

Find the perimeter of the triangle with vertices  d(3, 4),  e(8, 7), and  f(5, 9). do not round before calculating the perimeter. after calculating the perimeter, round your answer to the nearest tenth.