M=(13;-2). If you have questions just message me. I hope this helps

notice, the 2/5 is just a "scalar" value, so you can just get the derivative of the variable part and slap the scalar as its factor.
Answer:
x = 9.5
Step-by-step explanation:
y=2x+20; x is any integer greater than or equal to 0, and y is an integer greater than or equal to 20.