straight line equation
known two points namely (3,4) and (4,1)
the formula looking for equations if known two points is
![(x2 - x1)/(x1 - x) = (y2 - y1)/(y1 - y)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i1ct63iquc22gjx354yfgd1cab8g4iqdlk.png)
You can enter the numbers provided above into the formula
![(x2 - x1)/(x1 - x) = (y2 - y1)/(y1 - y) \\ (4 - 3)/(3 - x) = (1 - 4)/(4 - y) \\ (1)/(3 - x) = ( - 3)/(4 - y) \\ - 9 + 3x = 4 - y \\ y = - 3x + 13](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ja59wp2tg8tjaapyqyqwf6b9vzjbpjzcqc.png)
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