The two adjacent sides of a rectangle are 2x^{2} – 5xy + 3z^{2} and 4xy – x^{2} – z^{2}. Find its perimeter.
Adjacent sides of a rectangle are
2x^{2} – 5xy + 3z^{2} and 4xy – x^{2} – z^{2 }
∴ Perimeter = 2(2x^{2} – 5xy + 3z^{2} + 4xy – x^{2} – z^{2})
= 4x^{2} – 10xy + 6z^{2} + 8xy – 2x^{2} – 2z^{2}
= 2x^{2} – 2xy + 4z^{2}