straight line equation
known two points namely (3,4) and (4,1)
the formula looking for equations if known two points is

You can enter the numbers provided above into the formula

You can check the function is true or false
(3,4) 3=x and 4=y
y = -3(3) + 13
y = -9 + 13
y = 4 ✔️
*additional :
y = -3x + 19 ===== f(x) = -3x + 19