Simplify the expression 21b^4 - 3b by combining like terms

4. a spring scale is constructed so that each 0.10-n increment is separated by 0.50 cm. what spring constant is necessary for the scale to be accurate? -1.0n/cm -0.10n/cm -9.8 n/cm -0.20n/cm

Can someone me out here and the tell me the greatest common factor

Standard deviation of 19,29,21,22,23