Answer:
24x + 6
Step-by-step explanation:
add the lengths of the 4 pieces together
4x + 3 - 12x + 7 + 42x - 9 - 10x + 5 ← collect like terms
= (4 - 12 + 42 - 10)x + (3 + 7 - 9 + 5)
= 24x + 6
