0.2778 this is the answer for your question
Letter D
1-sin^2(x) = cos^2(x)
= sin^2(x)/cos^2(x)
= tan^2(x)
Hey mate here is your answer.
➛ 6(x-2) = 4(x+3)
➛ 6x-12 = 4x + 12
➛ 6x - 4x = 12 + 12
➛ 2x = 24
➛ x = 
⛬ x = 12
If y=mx+b,

You can't differentiate a constant, so dy/dx=m.