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## Answers

Quadratic Formula = D = b² - 4ac

= (7)² - 4(12)(-10)

= 49 + 480

= 529

Now

x =

__- b + √D__, x =

__-b - √D__

2a 2a

x =

__-7 + 23__, x =

__-7 - 23__

24 24

x = 16/24 , x = -30/24

x = 2/3 , x = -5/4

or,12x²+7x-10

As the equation is of the form +,+,-,find mentally 2 numbers whose sum is +7 and product is 12*(-10)=-120.One number will be positive and the other negative such that +ve no. > -ve no. (As their sum is a postive number)Such numbers are +15 and -8.

Therefore,the equation can be written as:

12x²+15x-8x-10

factorizing the (1st and 2nd ) and (3rd and 4th) terms together,we get

3x(4x+5)-2(4x+5)

or,(3x-2)(4x+5)=0

Either 3x-2=0 or 4x+5=0

Either 3x=2 or 4x=-5

Either

__x=2/3 or x=-5/4__

__Ans:The 2 roots of the equation are: x=2/3 or -5/4.__