Write 5.8 as a mixed number in simplest form

Aline passes through 3,7 and 6,9 what equation represents the line

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

Estimate the area under the curve f(x) = 16 - x^2 from x = 0 to x = 3 by using three inscribed (under the curve) rectangles. answer to the nearest integer.