Yes it is because there is an equal sign, a variable, and a plus sign
We can determine whether an equation is linear or quadratic just by looking at how the equation is written. In this case the given equation written as 3m+8=15 is not a quadratic equation
No, the equation is not quadratic because a quadratic is alsways 0
DISCLAIMER: I assume the '8' has an m and 3m has 'squared ²'
a= 3, b= 8, c= -15
because of the gravity of the erth