Write an equivalent expression using a commutative or associative law, as indicated.(4x + 7y) + 7z; associative

A. 4x + 7y + 7z
B. 4x + (7y + 7z)
C. (7y + 4x) + 7z
D. (4x + 7y + 7z)

Answer: B

Mathematics

You might also like to view...

Solve the problem.The differential equation for a falling body near the earth's surface with air resistance proportional to the velocity v is dv/dt = -g - av, where g = 32 feet per second per second is the acceleration due to gravity and a > 0 is the drag coefficient. This equation can be solved to obtain v(t) = (v0 - v?)e-at + v?, where v0 = v(0) and v? = -g/a = v(t), the terminal velocity.This equation, in turn, can be solved to obtain y(t) = y0 + tv? + (1/a)(v0 - v?)(1 - e-at) where y(t) denotes the altitude at time t. Suppose that a ball is thrown straight up from ground level with an initial velocity v0 and drag coefficient a. Write an equation in

terms of v0, g, and a for T, the time when the ball hits the ground.

A. -gT +  ln   = 0
B. -gT +   (1 - e^-aT) = 0
C. -aT +   (1 - e^-aT) = 0
D. -gT +   (1 - e^-aT) = 0