91Ó°ÊÓ

Write each English phrase as an algebraic expression. Then simplify the expression. Let \(x\) represent the number. the product of 3 and a number, which is then subtracted from the product of 12 and a number

Write each English phrase as an algebraic expression. Then simplify the expression. Let \(x\) represent the number. nine times the product of 3 and a number

Write each English phrase as an algebraic expression. Then simplify the expression. Let \(x\) represent the number. nine increased by the product of 3 and 2 less than a number

In Exercises \(81-88,\) simplify each algebraic expression by removing parentheses and brackets. $$3[5(x-2)+1]$$

In Exercises \(89-92,\) express each sentence as a single numerical expression. Then use the order of operations to simplify the expression. Subtract 11 from \(9 .\) Multiply this difference by \(2 .\) Raise this product to the fourth power.

In Palo Alto, California, a government agency ordered computer-related companies to contribute to a pool of money to clean up underground water supplies. (The companies had stored toxic chemicals in leaking underground containers.) The mathematical model $$C=\frac{200 x}{100-x}$$ describes the cost, \(C\), in tens of thousands of dollars, for removing \(x\) percent of the contaminants. Use this formula to solve Exercises \(101-102\). a. Find the cost, in tens of thousands of dollars, for removing \(50 \%\) of the contaminants. b. Find the cost, in tens of thousands of dollars, for removing \(80 \%\) of the contaminants. c. Describe what is happening to the cost of the cleanup as the percentage of contaminant removed increases.

A subtraction is expressed as addition of an opposite. Find this sum, indicated by a question mark. 7-10=7+(-10)=?

Write a numerical expression for each phrase. Then simplify the numerical expression by performing the given operations. The quotient of \(-18\) and the sum of \(-15\) and 12

Write a numerical expression for each phrase. Then simplify the numerical expression by performing the given operations. The difference between \(-6\) and the quotient of 12 and \(-4\)

Simplify: \(-8-2-(-5)+11 .\) (Section 1.6, Example 3)