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Q.3 Find the value of the following expressions, when x = –1:
(i) 2x – 7
(ii) – x + 2
\((iii) x^2 + 2x + 1\)
\((iv) 2x^2 – x – 2\)
Answer :

(i) 2x – 7
= (2 × -1) – 7
= – 2 – 7
= – 9
(ii) – x + 2
= – (-1) + 2
= 1 + 2
= 3
\((iii) x^2 + 2x + 1\)
\(= (-1)^2 + (2 × -1) + 1\)
= 1 – 2 + 1
= 0
\((iv) 2x^2 – x – 2\)
\(= (2 × (-1)^2) – (-1) – 2\)
= (2 × 1) + 1 – 2
= 2 + 1 – 2
= 3 – 2
= 1