SSC CGL Tier-1 practice question
Find the value of \(x2 - y2\) if \(x = 7\) and \(y = 6\).
From a SSC CGL Tier-1 Quantitative Aptitude practice set · Quantitative Aptitude
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Correct answer: (C) 13
We use the algebraic identity:
\[
x2 - y2 = (x - y)(x + y)
\]
Substitute \(x = 7\) and \(y = 6\):
\[
x2 - y2 = (7 - 6)(7 + 6) = 1 \times 13 = 13
\]
Alternatively:
\[
x2 - y2 = 72 - 62 = 49 - 36 = 13
\]
\[
x2 - y2 = (x - y)(x + y)
\]
Substitute \(x = 7\) and \(y = 6\):
\[
x2 - y2 = (7 - 6)(7 + 6) = 1 \times 13 = 13
\]
Alternatively:
\[
x2 - y2 = 72 - 62 = 49 - 36 = 13
\]
हिंदी में प्रश्न
यदि \(x = 7\) और \(y = 6\) हो, तो \(x2 - y2\) का मान ज्ञात कीजिए।
उत्तर जाँचने के लिए किसी विकल्प पर टैप करें।
उत्तर और व्याख्या देखें
सही उत्तर: (C) 13
बीजगणितीय सर्वसमिका का उपयोग करने पर:
\[
x2 - y2 = (x - y)(x + y)
\]
\(x = 7\) और \(y = 6\) रखने पर:
\[
x2 - y2 = (7 - 6)(7 + 6) = 1 \times 13 = 13
\]
वैकल्पिक रूप से:
\[
x2 - y2 = 72 - 62 = 49 - 36 = 13
\]
\[
x2 - y2 = (x - y)(x + y)
\]
\(x = 7\) और \(y = 6\) रखने पर:
\[
x2 - y2 = (7 - 6)(7 + 6) = 1 \times 13 = 13
\]
वैकल्पिक रूप से:
\[
x2 - y2 = 72 - 62 = 49 - 36 = 13
\]
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