Q. 1 J4.2( 13 Votes )

Find the errors and correct the following mathematical sentences

Substitute x = – 3 in

(a) x2 + 7x + 12 = (–3)2 + 7 (–3) + 12 = 9 + 4 + 12 = 25

Answer :

If LHS is


x2 + 7x + 12


Then RHS would be


x2 + 7x + 12


Putting x = (-3)


= (–3)2 + 7 (–3) + 12


= 9 + (-21) + 12


= 21-21


= 0


The error is (-21) instead of 4 and end result 0 instead of 25


Hence putting x = (-3) in x2 + 7x + 12 results to 0


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