Find 2r² + 3s³ - r² + 4t² - r² if r = −2, s = −3, and t = 5.

Solution:

Given:

Equation is 2r² + 3s³ - r² + 4t² - r²

⇒ Sorting the like terms and solving,

= (2r² - r² - r²) + 3s³ + 4t²

= 3s³+ 4t²

Substituting the given values of s = -3, and t = 5,

3 (-3)³+ 4 (5)² 

= - 81 + 100

= 19

Hence, the required value is 19.

Find 2r² + 3s³ - r² + 4t² - r² if r = −2, s = −3, and t = 5.

Summary:

The value of the equation 2r² + 3s³ - r² + 4t² - r² if r = −2, s = −3, and t = 5 is 19.