Ex.12.3 Q8 Algebraic Expressions Solution - NCERT Maths Class 7

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Question

 (i) If \(z = 10\), find the value of \(z^3 – 3(z – 10)\).

(ii) If \(p = \,– 10\), find the value of \(p^2 – 2p\, – 100\)

Text Solution

Steps:

First simplify the expression

\[\begin{align}&={{z}^{3}}-3z+30  \\& \text{Now putting value of }z=10  \\ &={{\left( 10 \right)}^{3}}-\left( 3\times 10 \right)+30  \\&=1000-30+30  \\\text{ Ans } &=1000  \\\end{align}\]

(ii) If \( p = \,– 10\), find the value of \(p^2 – 2p \,– 100\)

Put value of \(p = -10\) to solve the expression

\[\begin{align}&= {\left( { - 10} \right)^2} - \left( {2 \times - 10} \right) - 100\\&= 100 + 20 - 100\\{\text{Ans}} &= 20\end{align}\]