Question

Q1. Add: 3x² - 4xy - 8y², 6xy - 9x² - 3y², 8y² - 6xy - 5x²

Answer 1

Given 3 equations are:

• 3x² - 4xy - 8y²
• 6xy - 9x² - 3y²
• 8y² - 6xy - 5x²

We have to add the three of them,

(3x² - 4xy - 8y²) + (6xy - 9x² - 3y²) + (8y² - 6xy - 5x²)

Add the terms which have same coefficients..

⇒ (3x² - 9x²  - 5x²) + (6xy - 6xy - 4xy) + (8y² - 9y² - 8y²)

⇒ (-11x²) + (-4xy) + (-9y²)

⇒ -11x² - 4xy - 9y²

⇒ - (11x² + 4xy + 9y²)

$\boxed{\bold{-(11x^2 + 4xy + 9y^2)}}}$