PLEASE HELP!!

Solving problems with hcf and lcm

A small gardening allotment has dimensions 221 cm by 153 cm.
David wants to see how many square based planting spaces he can make in this
allotment.
If he wants to divide this allotment space into squares with the greatest
possible side length, how many squares will there be in the allotment?

What is negative 3/9 times negative 2/8 ?

For the quadratic function [tex]y=(x+4)^2-1[/tex] , do the following: a) rewrite the function in the standard form, b) rewrite the function in intercept form, c) find the vertex, d) find the y-intercept, e) find the x-intercepts.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.