Find the value of the following expressions, when $x=-1$
$(i)$. $2x-7$
$(ii)$. $-x+2$
$(iii)$. $x^2+2x+ 1$
$(iv)$. $2x^2-x-2$

AcademicMathematicsNCERTClass 7

Given: 

$(i)$. $2x-7$

$(ii)$. $-x+2$

$(iii)$. $x^2+2x+ 1$

$(iv)$. $2x^2-x-2$


To do: To find the value of the given expressions, when $x=-1$

Solution: 

$(i)$. $2x-1$


$=2\times\ (-1)-7$


$=-9$


$(ii)$. $-x+2$


$=-(-1)+2$


$=1+2$


$=3$


$(iii)$. $x^2+2x+1$


$=(-1)\ \times\ (-1)+2\ \times\ (-1)+1$


$=1-2+1$


$=0$


$(iv)$. $2x^2-x-2$


$=2(-1)\ \times\ (-1)-(-1)-2$


$=2+1-2=1$

raja
Updated on 10-Oct-2022 13:38:20

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