dy/dx = 8(8x - 5)(4x² - 5x )^ 7
differentiate using the ' chain rule '
dy/dx = 8(4x² - 5x)^ 7 × d/dx (4x² - 5x)
= 8(4x² - 5x)^ 7 × (8x - 5)
= 8(8x - 5)(4x² - 5x)
The two numbers are 12 and 16. 12 + 6 = 18. 6 doubled is 12. 12 plus 6 equals 18.
The answer to this question is D.