If x² + y² = 34 and xy = 15, find (x + y)².

64. (x + y)² = x² + 2xy + y² = 34 + 2(15) = 34 + 30 = 64. The value 4 is (x − y)² = 34 − 30, a common mix-up between the two square identities.

If $x^{2} + y^{2} = 34$ and $x y = 15$ , find $(x + y)^{2}$ .

Class 9PolynomialsPolynomials

(x + y)^{2} = x^{2} + 2 x y + y^{2} = 34 + 2 (15) = 34 + 30 = 64

. The value 4 is

(x - y)^{2} = 34 - 30

, a common mix-up between the two square identities.

Answer: A) 64

By number of terms:
- **Monomial**: 1 term (e.g.

5 x^{3}

)
- **Binomial**: 2 terms (e.g.

x^{2} + 3

)
- **Trinomial**: 3 terms (e.g.

x^{2} + 2 x + 1

)

By degree:
- **Linear** (degree 1):

3 x - 5

- **Quadratic** (degree 2):

x^{2} - 4

- **Cubic** (degree 3):

2 x^{3} + x - 1

- **Biquadratic** (degree 4):

x^{4} + 1

A polynomial can fit multiple categories.

5 x^{3}

is both a monomial and a cubic.

Don't just memorise the answer — build a daily practice habit.