(2a² - 3ab + 5b²) - (a² - 2ab + 3b²) First distribute - into (a² - 2ab + 3b²)
(2a² - 3ab + 5b²) + (-)a² - (-)2ab + (-)3b² [two negative signs cancel each other out and become positive]
(2a² - 3ab + 5b²) - a² + 2ab - 3b² Now combine like terms (terms that have the same variable and power/exponent)
2a² - a² - 3ab + 2ab + 5b² - 3b² (I rearranged the terms so the like terms are next to each other)
a² - ab + 2b² Your answer is the 4th option
