Question

ind the value of the following using $(x+a)(x+b)=x^2+(a+b)+ab$
$9.8\times 9.6$

Answer 1

We have,

$9.8\times 9.6$

$(10-0.2)(10-0.4)$

We know that

$(x+a)(x+b)=x^2+(a+b)x+ab$

Therefore,

$\Rightarrow {10}^2-(0.2+0.4)10+0.2\times 0.4$

$\Rightarrow 100-\left(0.6\right)10+0.08$

$\Rightarrow 100-6+0.08$

$\Rightarrow 94.08$

Hence, this is the answer.