Gradient of line = \(\frac{\text{Change in y}}{\text{Change in x}}\) = \(\frac{y_2 - Y}{x_2 - x}\) 

y\(_2\)  = 0\(_1\) 

Y\(_1\)  = 4 

x\(_2\)  = 3 and x\(_1\)  = 0

\(\frac{y_2 - y_1}{x_2 - x_1} = \frac{0 - 4}{3 - 0} = \frac{-4}{3}\)

Equation of straight line y = mx + c

Where m = gradient and c = y 

intercept = 4 

y = -\(\frac{4}{3}\)x + 4 multiply through by 3

3y = -4x + 12