Easy Algebra Step-by-Step

236 Answer Key

c. y x

x

=

−

91 x+

5

The domain is the set of all real numbers except 5.

d. y x

x

=

−

25 x +

4

2

2

Set x^2 − 4 = 0 and solve.

x= ±2 The domain is the set of all real numbers except 2 and −2.

4. a. f() 2 55 222 + − 335433 = 10 − 373

b. f()−)= 5 − 12 + − 35 = 13 − = 53 − = 2

c. f() 6 55 626 − 353 833 = 54 () 2 33 = 10 23

d. f()− )= 5 − 32 + − 35 = − 13 − There is no real number solution because the

square root of a negative number is not a real number.

5. Only graphs b and c are functions.


6. y= 4 x + 1

Chapter 20 Systems of Equations

Exercise 20

1. xy

24 yy=−

27 xy+=y

x = 2 y − 4

2(2y − 4) +y= 7

4 y − 8 + y = 7

5 y= 15

y= 3

2 x+ 3 = 7

2 x = 4

x= 2

x= 2 and y = 3 is the solution.

2. 43
   313

xy

xy 33

y= 4 x − 3

x −3(4x − 3) = −13

x − 12x + 9 = −13

−11x+ 9 = −13

−11x = −22

x= 2

4(2) − y = 3

8 − y= 3

−y = −5

y= 5

x= 2 and y = 5 is the solution.