Home » What value of Q will make the expression 4×2 + 5x + Q a complete…

What value of Q will make the expression 4×2 + 5x + Q a complete…

What value of Q will make the expression 4x2 + 5x + Q a complete square?
  • A.
    (frac{25}{16})
  • B.
    (frac{25}{64})
  • C.
    (frac{5}{8})
  • D.
    (frac{5}{4})
Correct Answer: Option A
Explanation

4x2 + 5x + Q
To make a complete square, the coefficient of x2 must be 1
= x2 + (frac{5x}{4}) + (frac{Q}{4})
Then (half the coefficient of x2) should be added
i.e. x2 + (frac{5x}{4}) + (frac{25}{64})
∴ (frac{Q}{4}) = (frac{25}{64})
Q = (frac{4 times 25}{64})
= (frac{25}{16})