Respuesta :

First, simplify
2r² + 3s² - r² + 4t² - r²
= 2r² - r² - r² + 3s² + 4t²
= 3s² + 4t²

Second, input the number
3s² + 4t²
= 3(-3)² + 4(5)²
= 3(9) + 4(25)
= 27 + 100
= 127