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Find the values of the following expressions for \({x}={2}.\) (i) \({x}+{4}\) (ii) \({4}{x}-{3}\) (iii) \({19}-{5}{x}^{{2}}\) (iv) \({100}-{10}{x}^{{3}}\)
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Question

Find the values of the following expressions for \({x}={2}.\) (i) \({x}+{4}\) (ii) \({4}{x}-{3}\) (iii) \({19}-{5}{x}^{{2}}\) (iv) \({100}-{10}{x}^{{3}}\)

Answer

(i) \({x}+{4}={2}+{4}={6}\)

(ii) \({4}{x}-{3}={4}{\left({2}\right)}-{3}\)

\(={8}-{3}={5}\)

(iii) \({19}-{5}{x}^{{2}}={19}{5}{\left({2}\right)}^{{2}}\)

\(={19}-{20}=-{1}\)

(iv) \({100}-{10}{x}^{{3}}\)

\(={100}-{10}{\left({2}^{{3}}\right)}\)

\(={100}-{80}={20}\)

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