+91-87964 74404
FlagBACK
Question icon
Grade 1210 grade maths

Find the roots of the following quadratic equations, if they exist, by the method of completing the square:
2x^2 + x – 4 = 0

Profile image of Pawan Prajapati
5 Years agoGrade 12
Answers icon

2 Answers

Profile image of Harshit Singh
5 Years ago
Dear Student

⇒ 2x^2 + x = 4
Dividing both sides of the equation by 2,
⇒ x^2 +x/2 = 2
Now on adding (1/4)^2 to both sides of the equation,
⇒ (x)^2 + 2 × x × 1/4 + (1/4)^2 = 2 + (1/4)^2
⇒ (x + 1/4)^2 = 33/16
⇒ x + 1/4 = ± √33/4
⇒ x = ± √33/4 - 1/4
⇒ x = ± √33-1/4
either
x = √33-1/4 or x = -√33-1/4

Thanks
Profile image of Ram Kushwah
5 Years ago
2x²+x-4=0
dividing both sides by 2
x²+x/2-2=0
Or x²+x/2=2
Multiplying both sides by 4
4x²+2x=8
adding both sides (1/2)²=1/4
4x²+2x+1/4=8+1/4
(2x)²+2*(2x)(1/2) +(1/2)² =33/4
(2x+1/2)²=33/4
2x+1/2 = ±√33/4 = ±1/2*√33
2x= ±1/2*√33-1/2
x = ±1/4*√33-1/4
x=(±√33-1)/4
Thus the roots of the equation are:
=(√33-1)/4 and =(-√33-1)/4
Thanks ,pl aprove
 

Other Related Questions on 10 grade maths

question mark

How do you find the Maclaurin series for tanx?

10 grade maths
1 Answer Available

Last Activity: 1 Year ago

question mark

Why is Axiom 5, in the list of Euclid’s axioms, considered a ‘universal truth’? (Note that the equation is not about the fifth postulate.)

10 grade maths
1 Answer Available

Last Activity: 1 Year ago

question mark

The smallest composite number is ______.

(a) 2

(b) 4

(c) 1

(d) None of these

10 grade maths
1 Answer Available

Last Activity: 1 Year ago

question mark

Find the arithmetic mean of the first ten odd natural numbers.

10 grade maths
1 Answer Available

Last Activity: 1 Year ago

question mark

A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30 km upstream and 21 km downstream in 6 hours and 30 minutes. The speed of the boat in still water is

A. 10 km/hr

B. 4 km/hr

C. 14 km/hr

D. 6 km/hr

10 grade maths
1 Answer Available

Last Activity: 1 Year ago