The graph of a line in the x y-plane passes through the point (1, 4) and crosses the x-axis at the point (2, 0) . The line crosses the y-axis at the point (0, b) . What is the value of b ?

The correct answer is: b = 8

HINT – Form equation of a straight line using two point form or point slope form
SOLUTION -  It is given that the line pass through two points viz.
(1 , 4) and (2 , 0)
Slope of the line =  where (x₁ , y₁) and (x₂ , y₂) are two points through which line is passing.
So, slope of the line 
We know that equation of a line is given by (y – y₁) = m (x – x₁) where m is the slope of the line. This is called point slope method.
Equation of the line is (y – 0 ) = - 4 (x – 2)
y = - 4x + 8
4x + y = 8             ---- (1)
Now, given point is (0 , b). Substituting in equation (1)
We get, 4(0) + b = 8
b = 8
Hence, answer is b = 8