Find each sum or difference by combining the parts that are alike.
a. 417+231 = _____ hundreds + _____ tens + _____ ones + _____ hundreds + _____ tens + _____ ones
= _____ hundreds + _____ tens + _____ ones
b. (4x²+x+7)+(2x²+3x+1)
c. (3x³−x²+8)−(x3+5x2+4x−7)
d. 3(x³+8x)−2(x³+12)
e. (5−????−????²)+(9????+????²)
f. (3p+1)+6(p−8)−(p+2)