Question

What number is represented by −3x²+√2x+1/2 when x=√2?

Answer 1

at x =
`√(2)`,
`-3x^(2) + √(2)x + (1)/(2)` = -3.5

Explanation:

The given equation is
`-3x^(2) + √(2)x + (1)/(2)`

Now, substitute the value of x =
`√(2)` in the above equation.

The given equation simplifies to,

`-3(√(2))^(2) + (√(2))(√(2)) + (1)/(2)`

now,
`√(2) . √(2)  = 2, \textrm{and} (√(2) )^(2) = 2`

So, the equation become

-3(2) + 2 + (1/2) =
`-6 + 2 + (1)/(2)   = -4 + (1)/(2) = (-8 + 1)/(2)  = (-7)/(2)`

= -3.5

So, at x =
`√(2)`,
`-3x^(2) + √(2)x + (1)/(2)` = -3.5