20% of 400 is what number

Write 5(6x+4)-2(5x-2) in the form a(bx+c) where a,b and c integers and a> 1

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|

There were 32 volunteers to donate blood. unfortunately, nn of the volunteers did not meet the health requirements, so they couldn't donate. the rest of the volunteers donated 470 milliliters each.