How do I solve this question?

Question

The straight line ax + y = b passes through the points (-1,1) and (-5,4). The product of the two numbers a and b rounded to two decimal places is_______.

Answer 1

Use the 2 given points to find a and b, then evaluate ab.

a(-1) + 1 = b

a(-5) + 4 = b

b = 1 - a

b = 4 - 5a

1 - a = 4 - 5a

-3 = -4a

a = 3/4

b = 1 - 3/4 = 1/4

You can finish from here.