NCERT Class 10th solution of Exercise 4.1 NCERT Class 10th solution of Exercise 4.2 NCERT Class 10th solution of Exercise 4.4 NCERT Class 10th Maths Projects Like, share, and Subscribe. Exercise 4.3 Q1. Find the roots of the following quadratic equations, if they exist, by the method of completing the square : i) `2x^2-7x+3=0` ii) `2x^2+x-4=0` iii) `4x^2+4sqrt3x+3=0` iv) `2x^2+x+4=0` Sol. : i) `2x^2-7x+3=0` compare with `ax^2+bx+c=0` where `a=2, b=-7` and `c=3` `=b^2-4ac` `=(-7)^2-4(2)(3)` `=49-24` `=25>0` The roots exist. By completing the square `2x^2-7x+3=0` `x^2-(7x)/2+3/2=0` `x^2-(7x)/2=-3/2` [Add `(7/4)^2` both sides] `x^2-(7x)/2+(7/4)^2=-3/2+(7/4)^2` `x^2-(2(7x))/(2(2))+(7/4)^2=-3/2+49/16` `(x-7/4)^2=(-24+49)/16` `(x-7/4)^2=25/16` `(x-7/4)^2=(5/4)^2` `(x-7/4)^2-(5/4)^2=0` [`a^2-b^2=(a+b)(a-b)`] `(x-7/4-5/4)(x-7/4+5/4)=0` `(x-12/4)(x-2/4)=0` `(x-3)(x-1/2)=0` `x-3=0` `x=3` `x-1/2=0` `x=1/2` Answer : `x=3, 1/2` ii) `2x^2+x-4=0` compare with `ax^2+bx+c=0` where `a=2, b=1` and
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