Знайди значення виразу 2(3х – 5у) – 5(2х – 4у), якщо 5y – 2x = –17.
Розв'язок:
2(3х – 5у) – 5(2х – 4у) = 6х – 10у – 10х + 20у = -4х + 10у = 10у – 4х = 2 ⋅ 5у – 2 ⋅ 2х = 2 ⋅ (5у – 2х) = 2 ⋅ (-17) = -34
2(3х – 5у) – 5(2х – 4у) = 6х – 10у – 10х + 20у = -4х + 10у = 10у – 4х = 2 ⋅ 5у – 2 ⋅ 2х = 2 ⋅ (5у – 2х) = 2 ⋅ (-17) = -34