Dividin a number by 10 exponent, how is the decimal point moved

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Worth 100 points need the answers asap first row -x^2 2x^2 (x/2)^2 x^2 x is less than 2 x is greater than 2 x is less than or equal to 2 x is greater than or equal to 2 second row -5 -5/2 4 5 •2 is less than x& x is less than 4 •2 is less than or equal to x & x is less than or equal to 4 •2 is less than or equal to x& x is less than 4 •2 is less than x& x is less than or equal to 4