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Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify. Raise each side to the power . 3 2 The correct answer is D. ANSWER

Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

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Page 1: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

Standardized Test PracticeEXAMPLE 3

SOLUTION

4x2/3 = 36 Write original equation.

x2/3 = 9 Divide each side by 4.

(x2/3)3/2 = 93/2

x = ±27 Simplify.

Raise each side to the power .32

The correct answer is D.

ANSWER

Page 2: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

Solve an equation with a rational exponentEXAMPLE 4

Solve (x + 2)3/4 – 1 = 7.

(x + 2)3/4 – 1 = 7

(x + 2)3/4 = 8

(x + 2)3/4 4/3= 8 4/3

x + 2 = (8 1/3)4

x + 2 = 24

x + 2 = 16

Write original equation.

Add 1 to each side.

Simplify.

Apply properties of exponents.

Raise each side to the power .43

Simplify.

x = 14 Subtract 2 from each side.

Page 3: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

Solve an equation with a rational exponent

EXAMPLE 4

The solution is 14. Check this in the original equation.

ANSWER

Page 4: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

5. 3x3/2 = 375

3x3/2 = 375 Write original equation.

x3/2 = 125 Divide each side by 3.

(x3/2)2/3 = (125)2/3 Raise each side to the power .2

3

x = 25 Simplify.

Page 5: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

6. –2x3/4 = –16

Write original equation.

x3/4 = 8 Divide each side by –2.

(x3/4)4/3 = 84/3 Raise each side to the power .4

3

Simplify.

x = (81/3)4 Apply properties of exponent.

x = 16

–2x3/4 = –16

Page 6: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

23

x1/5 – = –27.

Write original equation.

(x1/5 )5= 35

Divide each side by –2/3.

x = 243

Raise each side to the power 5.

Simplify.

23

x1/5 – = –2

x1/5= 3

Page 7: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

8. (x + 3)5/2 = 32

(x + 3)5/2 = 32 Write original equation.

[(x+ 3)5/2]2/5 = 322/5 Raise each side to the power 2/5.

Apply properties of exponent. x + 3 = (32• )2

51

x + 3 = 4

x = 1 Simplify.

Simplify.

Page 8: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

9. (x – 5)4/3 = 81

Write original equation.

[(x – 5)4/3]3/4 = (81)3/4 Raise each side to the power 3/4.

Apply properties of exponent. x – 5 = (811/4)3

x – 5 = ±33

x – 5 = ±27 Simplify.

Simplify.

(x – 5)4/3 = 81

x – 5 = 27 or x – 5 = 27

x = 32 or x = –22

Let (x – 5) equal 27 and –27.

Subtract 5 from both sides of each equation.

Page 9: Standardized Test Practice EXAMPLE 3 SOLUTION 4x 2/3 = 36 Write original equation. x 2/3 = 9 Divide each side by 4. (x 2/3 ) 3/2 = 9 3/2 x = ±27 Simplify

GUIDED PRACTICE for Examples 3 and 4

Solve the equation. Check your solution.

10. (x + 2)2/3 + 3 = 7

Write original equation.

(x + 2)2/3 = 4

Raise each side to the power 3/2.

Apply properties of exponent.

x +2 = 8 or x + 2 = 8

Simplify.

Simplify.

(x + 2)2/3 +3 = 7

[(x + 2)2/3]3/2 = 43/2

x + 2 = (41/2)3

x = 10 or 6

Subtract each side by 3.