Final answer:
To find x in the equation: 5x + 3 + 8x - 4 = 90, combine like terms and solve for x. The correct answer is option D) 17.
Step-by-step explanation:
To find x in the equation: 5x + 3 + 8x - 4 = 90, we need to simplify the equation and solve for x.
Combining like terms, we get 13x - 1 = 90.
Adding 1 to both sides, we have 13x = 91.
Dividing both sides by 13, we find that x = 7. Therefore, the correct answer is option D) 17.