(solve by complete squaring method)
Answers
SOLUTION :-
=>Given that, 2x² - 7x + 3 = 0 .
=>2x²/2 - 7x/2 + 3/2 = 0/2 ------(Divide by 2 on each sides).
=>.°. x² - 7x/2 + 3/2 = 0
=>.°. x² - 7x/2 = -3/2
=>Add 9/4 on each sides,
=>x² - 7x/2 + 9/4 = -3/2 + 9/4
=>x² - 7x/2 + 3/2 = -3/2 + 9/4
=>(x - 3/2)² = -6 + 9/4
=>(x -3/2)² = 3/4
=>x - 3/2 = √3/4
=>x - 3/2 = ± √3/2
=> x - 3/2 = √3/2 or x - 3/2 = - √3/2
=> x = 3+√3 / 2 or x = -3+√3 / 2
Given : 2x² –7x + 3 = 0
On dividing the whole equation by 2,
(x² - 7x/2 + 3/2) = 0
Shift the constant term on RHS
x² - 7x/2 = - 3/2
Add square of the ½ of the coefficient of x on both sides
On adding (½ of 7/2)² = (7/4)² both sides
x² - 7x/2 + (7/4)²= - 3/2 + (7/4)²
Write the LHS in the form of perfect square
(x - 7/4)² = - 3/2 + 49/16
[a² - 2ab + b² = (a - b)²]
(x - 7/4)² = (-3 × 8 + 49)/16
(x - 7/4)² = (-24 + 49)/16
(x - 7/4)² = 25/16
On taking square root on both sides
(x - 7/4) = √(25/16)
(x - 7/4) = ± 5/4
On shifting constant term (-7/4) to RHS
x = ± 5/4 + 7/4
x = 5/4 + 7/4
[Taking +ve sign]
x = (5 +7)/4
x = 12/4
x = 3
x = - 5/4 + 7/4
[Taking -ve sign]
x = (- 5 + 7)/4
x = 2/4
x = 1/2
Hence, the roots of the given equation are 3 & ½.