Westside Energy charges its electric customers a base rate of $6.00 per month, plus 15€ per kilowatt-hour (kWh) for the first 300 kWh used and

2€ per kWh for all usage over 300 kWh. Suppose a customer uses x kWh of electricity in one month.

(a) Express the monthly cost E as a piecewise defined function of x. (Assume E is measured in dollars.)

E(x) =

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(b) Graph the function E for 0 sxs 600.

E

60

50

L

40

30

20

10

E

60p

50

40

30

20

10

if 0 sxs 300

Read It

if 300 < x

100

200

X

300 400 500 600

100 200 300 400 500 600

Watch It

E

100

80

60

40

20

X

100 200 300 400 500 600

E

60

50

40

V

30

20

10

3

100 200 300 400 500 600