By decreasing the dimension by 1 unit, the area of a rectangle decreased from 40 square feet (on the left) to 28 square feet (on the right). Find the percent of the decrease in area.

Prove the statements. There are real numbers a and b such that

$$\sqrt { a + b } = \sqrt { a } + \sqrt { b }$$

.

Solve each equation. $\\$$6(3+n)=5(n-1)$

Use the graph below to answer the exercise.

The number of Internet-crime complaints decreased from 2011 to 2012 . Find the percent of decrease. Round to the nearest tenth of a percent.

Find bases for the null space and row space of A (b) A = [1 4 5 6 9, 3 -2 1 4 -1, -1 0 -1 -2 -1, 2 3 5 7 8]

Suppose demand, d, for a company's product at cost, x, is predicted by the function

$$d(x) = -0.25x^2 + 1,000$$

and the price, p, that the company can charge for the product is given by

$$p(x) = x + 16.$$

Find the company's revenue function.

The demand function for a certain commodity is p=20-0.05x. Find the consumer surplus when the sales level is 300. Illustrate by drawing the demand curve and identifying the consumer surplus as an area.

Solve each formula for the specified variable. $\\$$A=\pi a b$for$b$

Indicate whether the following lists of terms are like or unlike. See Example 2.

$$b^2 a,-\frac{7}{8} a b^2 {\hspace{0.1cm}} \underline{\hspace{1cm}}$$

Of 140 seventh-grade students. 15% earn the Presidential Physical Fitness Award. How many students earn the award?

Solve each equation. $\\$$4(x+3)=3(1+x)$

Add. $\\$$-3+10$

Find the solution to each of these recurrence relations with the given initial conditions. Use an iterative approach. a) $a_n = -a_{n-1}, a_0 = 5$. b) $a_n = a_{n-1} + 3, a_0 = 1$. c) $a_n = a_{n-1} - n, a_0 = 4.$ d) $a_n = 2a_{n-1} - 3, a_0 = -1$. e) $a_n = (n+1)a_{n-1}, a_0 =2$. f) $a_n = 2na_{n-1}, a_0 = 3$. g) $a_n = -a_{n-1} + n - 1, a_0 = 7$

Solve $\\$$4 b-8-b=10 b-3 b$