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.
- 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.
- Only graphs b and c are functions.
- y= 4 x + 1
Chapter 20 Systems of Equations
Exercise 20
- 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.
- 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.