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Sub 505 (Easy)|   Algebra|   Exponents|      
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Bunuel
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 08:27
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C
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5% (low)

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85% (00:47) correct 15% (01:07) wrong based on 200 sessions

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Tough and Tricky questions: Exponents.



If 5^5 × 5^7 = (125)^x , then what is the value of x?

A) 2
B) 3
C) 4
D) 5
E) 6

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C
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 08:57
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5^5 × 5^7 = 5^(5 + 7) = 5^12
125^3 = (5^3)^3 = 5^3X

Therefore 3x = 12, x = 4

Hence C
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 09:33
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5^5 = 125 x25 and 5^7 = 5* 125^2

5^5 * 5^7 = 125^4 hence x= 4.

Answer is C.
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 12:22
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Get everything in base 5 first: 5^5*5^7=125^x=5^(3x)
When multiple two identical bases with exponents, simply add the exponents together: 5^5*5^7 = 5^12
Now we have 5^12 = 5^(3x) and we can equate the exponents when the bases are the same to get x=4.

Choice C
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 20:56
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Answer = C = 4

\(5^5 * 5^7 = (125)^x\)

\(5^{12} = {(5^3)}^{x}\)

\(5^{12} = 5^{3x}\)

Bases are same, equating powers

3x = 12

x = 4
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 03 Dec 2014, 23:50
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5^5 × 5^7 = (125)^x
5^(5+7) = 5^3x
5^12 = 5^3x

since base is same, we can equate powers:
12 = 3x
x = 4

Ans. C) 4
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 04 Dec 2014, 07:26
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Bunuel

Tough and Tricky questions: Exponents.



If 5^5 × 5^7 = (125)^x , then what is the value of x?

A) 2
B) 3
C) 4
D) 5
E) 6

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Source: Chili Hot GMAT
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The correct answer is C.
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If 5^5 × 5^7 = (125)^x , then what is the value of x? 08 May 2020, 19:34
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If 5^5 × 5^7 = (125)^x , then what is the value of x?

5^5 × 5^7 = (125)^x
or,5^(5+7) = (5^3)^x
or,5^(12) = 5^(3x)
so,3x=12
or,x=4

correct answer C
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