All linear functions can be represented in the form of y = mx + c, where m = slope of the linear function and b = y-intercept.
In first option, y = 4x + 3
Here,
rate of change = 4 and it is constant.
power of x = 1
So, y = 4x + 3 is a linear function with slope = 4.
In second option,
y=1x(3) + 2
⇒y=3x−1 + 2
As per the condition of linear function, y = mx + c, the power of 'x' should be 1.
But the above function has a power of x as -1.
So, y=1x(3) + 2 is a non-linear function
In third option,
y=5(3x+2)+x
⇒y=16x+10
Rate of change = 16 and it is constant.
Power of x = 1.
So, y = 5(3x + 2) + x is a linear function with slope = 16.