Need with number 7 you i will give you ten points

Two different linear functions are shown below with two points given from each function. use slope-intercept form or point-slope form to find the equation of each. linear function a points: (–5, –2), (–5, 7) linear function b points: (7, –5), (–2, –5) function a has: the equation of line a is: function b has: the equation of line b is:

Asphere has a diameter of 10 in. what is the volume of the sphere?

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.