Write an expression in simplest form that represents the area of the banner

Which linear equations have an infinite number of solutions? check all that apply.  (x  –  3/7)  =  2/7(3/2x  –  9/14)8(x  +  2)  =  5x  –  1412.3x  –  18  =  3(–6  +  4.1x)(6x  +  10)  =  7(x  –  2)4.2x  –  3.5  =  2.1 (5x  +  8)

What is the number 321,000,000 in scientific notation? also what is the number? ?

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?