The sum of 4 + 9 times a number algebraic expression​

Simplify the expression. -2/5(10+15m-20n)

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.

The population of a bacteria colony grows by a consistent percentage each hour and can be modeled by the function y = 500(1.16)t. what does the value 500 represent in the function?