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Sub 505 (Easy)|   Algebra|      
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Bunuel
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When x is added to y the value is 12 and when y is subtracted from x 04 Jan 2017, 01:57
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C
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5% (low)

Question Stats:

89% (01:23) correct 11% (02:22) wrong based on 101 sessions

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When x is added to y the value is 12 and when y is subtracted from x the value is 7, what is the value of x^2 – y^2?

A. 193
B. 95
C. 84
D. 32
E. 19
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C
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When x is added to y the value is 12 and when y is subtracted from x 04 Jan 2017, 02:04
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Bunuel
When x is added to y the value is 12 and when y is subtracted from x the value is 7, what is the value of x^2 – y^2?

A. 193
B. 95
C. 84
D. 32
E. 19
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C
x+y=12
x-y=7
x=9.5,y=2.5
x^2-y^2=(x-y)(x+y)=(9.5-2.5)*(9.5+2.5)=(7)*(12)=84
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When x is added to y the value is 12 and when y is subtracted from x 04 Jan 2017, 08:17
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C option.
84. Multiply both equations an dget the answer
x2 - y2 = 84
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When x is added to y the value is 12 and when y is subtracted from x 04 Jan 2017, 11:41
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(x+y)(x-y)=x^2-y^2
=> 12*7=84
C.

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When x is added to y the value is 12 and when y is subtracted from x 06 Jan 2017, 22:48
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The key in solving this question is to convert statements into equations.
Given,
1)When x is added to y the value is 12.This means,x+y=12
2)when y is subtracted from x the value is 7.This means,x-y=7
Required:what is the value of x^2 – y^2?i.e.,x^2 – y^2=?
x^2 – y^2=(x-y)*(x+y)
=(7)*(12)
=84
So,correct answer choice is C
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When x is added to y the value is 12 and when y is subtracted from x 16 Dec 2023, 03:40
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