Simplify the following polynomial expression: \( (3x^2 - 4x + 7) + (2x^2 + 5x - 3) \)

Step 1 ：First, we group like terms together. The like terms are terms that have the same variable and exponent. So, we can rewrite the given expression as: \( (3x^2 + 2x^2) + (-4x + 5x) + (7 - 3) \)

Step 2 ：Next, we simplify each grouped term separately: \( 3x^2 + 2x^2 = 5x^2 \), \( -4x + 5x = x \), and \( 7 - 3 = 4 \)

Step 3 ：Then, we combine all of the simplified terms together to get the final simplified expression: \( 5x^2 + x + 4 \)