Beginning Algebra, 11th Edition

Brain Busters Perform each operation and express the answer in simplest form.

Solve each problem.

85.The radius of the circular top or bottom of a tin can with surface area S
and height his given by

What radius should be used to make a can with height 12 in. and surface

area 400?

86.If an investment of Pdollars grows to Adollars in 2 yr, the
annual rate of return on the investment is given by

First rationalize the denominator, and then find the annual

rate of return (as a percent) if $50,000 increases to $54,080.

r=

2 A- 2 P

2 P

.

in.^2

r=

• h+ 2 h^2 +0.64S
  2
  .

A 235 - 234 BA 2325 + 2320 + 2316 B A 234 + 232 BA 2316 - 238 + 234 B

A 232 - 1 BA 234 + 3 B A 239 + 5 BA 233 - 4 B

(^2242) A 3248 + (^5244) B (^6249) A 2249 - (^2427) B
234 A 232 - 3 B 235 A 4235 - 2325 B
SECTION 8.5 More Simplifying and Operations with Radicals 529
h
r
EXERCISES 87– 92
FOR INDIVIDUAL OR GROUP WORK
Work Exercises 87–92 in order,to see why a common student error is indeed an error.
87.Use the distributive property to write as a sum.
88.Your answer in Exercise 87should be. Why can we not combine these
two terms to get 48x?
89.Repeat Exercise 14from earlier in this exercise set.
90.Your answer in Exercise 89should be. Many students will, in error,
try to combine these terms to get. Why is this wrong?
91.Write the expression similar to that simplifies to 48x. Then write the
expression similar to that simplifies to.
92.Write a short explanation of the similarities between combining like terms and
combining like radicals.
30 + 1825 4825
30 + 18 x
4825
30 + 1825
30 + 18 x
615 + 3 x 2

RELATING CONCEPTS

Solve each equation. See Section 6.5.

96.x^2 - 6 x+ 9 = 0 97.x 1 x+ 22 = 3 98.x 1 x+ 42 = 21

12 x- 1214 x- 32 = 0 15 x+ 622 = 0 x^2 + 4 x+ 3 = 0

PREVIEW EXERCISES