Question

For what value of x: -3x^2 + 5x - 12 has maximum value?

Answer 1

Answer:

⇒−[(

5

x)

2

+2(

5

x)×(

5

1

)+(

5

1

)

2

]−(

5

1

)

2

+7

⇒−(

5

x+

5

1

)

2

+

5

1

−7

⇒

5

34

−(

5

x+

5

1

)

2

As (

5

x+

5

1

)

2

≥0

∴ max. value e at

5a

+

5

1

=0⇒

a=

5

1

Answer 2

Answer:

3x²+5x-12

3x²+(9-4)-12

3x²+9x-4x-12

3x(x+x)-4(x+3)

(x+3)(3x-4)

x=-3,4/3

so, x has maximum value for 4/3.