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QUADRATIC EQUATIONS

  • Solving Quadratic Equations Using

Formula Method

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General Form of a Quadratic Equation is

ax2 + bx + c = 0

To use this formula

we should have value

of a, b & c

Formula to

find value of ‘x’

3] Formula Method

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Solve the following by using formula method

i) 3q2 = 2q + 8

Sol :

3q2 = 2q + 8

∴ 3q2 – 2q – 8 = 0

On comparing with ax2 + bx + c = 0,

we get,

aq2 + bq + c = 0

3q2 – 2q – 8 = 0

a = 3,

b = – 2

& c = – 8

b2 – 4ac

= (– 2)2 –

= 4 + 96

= 100

4

(3)

(– 8)

∴ q =

∴ q =

∴ q =

∴ q =

or

q =

∴ q =

q =

or

∴ q =

2

or

q =

 

Standard

form

-

(- 2)

 

 

 

To use formula

we should have value

of a, b & c