Question

Using the identities of algebric expressions, the value of ${\left(4.9\right)}^2$ is .

• A. 24.01
• B. 25
• C. 23.6
• D. 24.25

Answer 1

The correct option is A 24.01

${\left(4.9\right)}^2={(5.0-0.1)}^2$

Using the identity $(a-b{)}^2=a^2-2ab+b^2$

${(5.0-0.1)}^2$= ${\left(5\right)}^2$ + ${\left(0.1\right)}^2$ - 2(5)(0.1)
$=25+0.01-1$
$=24.01$