question_answer

Find the value of:

(a) \[15625\times \left( -2 \right)+\left( -15625 \right)\times 98\]

(b) \[18946\times 99-\left( -18946 \right)\]

Answer:

\[\left( a \right)\text{ }15625\times \left( -2 \right)+\left( -15625 \right)\times 98\]

\[\left( -15625 \right)\times 2+\left( -15625 \right)\times 98\]

\[=\left( -15625 \right)\times \left( 2+98 \right)\]

\[=\left( -15625 \right)\times 100\]

\[=-\left( 15625\times 100 \right)\]

= -1562500

\[\left( b \right)\text{ }18946\times 99-\left( -18946 \right)\]

\[18946\times 99+18946\]

\[=\text{ }18946\times 99+18946\times 1\]

\[\left[ \therefore \text{ }18946=18946\times 1 \right]\]

\[=\text{ }18946\times \left( 99+1 \right)\]

\[[Using\,\,a\times b+a\times c=a\times (b+c)]\]

\[=\text{ }18946\times 100\]

= 1894600