The human hair has a width of about 6.5 · 10-5 meters. What is this width written in scientific notation?

Use the elimination method to solve the system of equations -x+5y=-4 and 4x+3y=16

Zoe placed colored blocks on a scale in science class. each block weighed 0.8 ounces. the total weight of all the colored blocks was 12.8 ounces. how many blocks did zoe place on the scale? write and solve an equation to find the answer.

What is the slope of the line that contains the points (4,8) and (9,8)? what type of line is it?