# Ex.9.2 Q5 Algebraic Expressions and Identities - NCERT Maths Class 8

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## Question

Obtain the product of

(i) $$\quad xy,\,yz,\,zx$$

(ii)  $$\quad a,\, - {a^2},\,{a^3}$$

(iii)$$\quad 2,\,4y,\,8{y^2},\,16{y^3}$$

(iv)$$\quad a,\,2b,\,3c,\,6abc$$

(v) $$\quad m,\, - mn,\,mnp$$

## Text Solution

What is known?

Expressions

What is unknown?

Product

Reasoning:

By using the distributive law, we can carry out the multiplication term by term.

Steps:

(i)

\begin{align} xy \times yz \times zx = {x^2}{y^2}{z^2}\end{align}

(ii)

\begin{align} a \times \left( { - {a^2}} \right) \times {a^3} = - {a^6}\end{align}

(iii)

\begin{align} & 2 \times 4y \times 8{y^2} \times 16{y^3} \\&= 2 \times 4 \times 8 \times 16 \times y \times {y^2} \times {y^3} \\ &= 1024{y^6}\end{align}

(iv)

\begin{align}& a \times 2b \times 3c \times 6abc \\ &= 2 \times 3 \times 6 \times a \times b \times c \times abc \\ &= 36{a^2}{b^2}{c^2}\end{align}

(v)

\begin{align} m \times \left( { - mn} \right) \times mnp = - {m^3}{n^2}p\end{align}

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