d. 3
[tex](6 + 8x) \div 2 = 5x \\ \times 2 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \times 2 \\ 6 + 8x = 10x \\ \: \: \: \: - 8x \: \: \: \: - 8x \\ 6 = 2x \\ \div 2 \: \div 2 \\ 3 = x[/tex]
you can check your answer by plugging out back in the formula
