Is 3x + 5x equivalent to 15x?

If n stands for number sold and c stands for cost per item, in which column would you use the formula: ? a. column d c. column f b. column e d. column g

What is the multiple zero and multiplicity of f(x) = (x ? 3)(x ? 3)(x + 5)? multiple zero is 3; multiplicity is 2 multiple zero is 5; multiplicity is 1 multiple zero is ? 5; multiplicity is 1 multiple zero is ? 3; multiplicity is 2

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.