Let's solve the expression step by step:

We are given the expression:

$(3x^2 + 5x - 10) + (x^2 + 5x - 2)$

1. Combine like terms:

   • Combine the $x^2$ terms: $3x^2 + x^2 = 4x^2$
   • Combine the $x$ terms: $5x + 5x = 10x$
   • Combine the constant terms: $-10 - 2 = -12$

2. Final simplified expression: $4x^2 + 10x - 12$

Would you like further details or explanations on any part of the process?

Here are 5 related questions:

1. How would you solve for $x$ in $4x^2 + 10x - 12 = 0$?
2. How do you factor a quadratic expression like $4x^2 + 10x - 12$?
3. What is the significance of combining like terms in algebraic expressions?
4. How can you graph the equation $y = 4x^2 + 10x - 12$?
5. Can this expression be simplified further through factoring or other methods?

Tip: Always double-check your steps when combining like terms to avoid errors!