Three friends bought 4, 6, and 8 books. This table shows the cost of the books.
Number of Books 4 6 8
Cost ($) 30 45 60

What is the constant of proportionality?

A. 2
B. 7.5
C. 15
D. 30

Select the correct answer from each drop-down menu. rewrite the formula to find voltage. the formula for electrical power (p, in watts) is where v is the voltage in volts and r is the resistance in ohms. for a particular brand of water heater, r is 32 ohms and p is 0.5 watts. the formula to find v is , and the voltage at which the heater operates is volts.

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Solve each equation using the quadratic formula. find the exact solutions. 6n^2 + 4n - 11