Question

Using identities, evaluate:
${71}^2$

• A. 5401
• B. 5041
• C. 4911
• D. 4941

Answer 1

The correct option is B 5041

${71}^2=(70+1{)}^2=(70{)}^2+2\times 70\times 1+(1{)}^2$
$\left[Usingidentity\right(a+b{)}^2=a^2+2ab+b^2]$
$=4900+140+1=5041$