MHB How Do You Solve Linear Equations with Given Coordinates?

[Sarahq]

 

[Opalg]

Hi Sarahq, and welcome to MHB!

For your Problem 5, you should notice that as $X$ increases by $1$, $Y$ decreases by $2$. So the equation between $X$ and $Y$ should start as $Y = \dfrac{-2}1X \ldots$. You should then be able to find the constant term to complete the equation.

 

[knoppi]

Hi Sarahq,

The formula for linear equations is
\[ y = mx+b \]
m = slope and b = shift on the y-axis.

The following formula is used to calculate the slope m
\[ m = \frac{y_2-y_1}{x_2-x_1} \]
(here -2/1 = -2)
Use x-, y-values and m to calculate b:
\[ -23 = -2 * 13 + b \]
solve for b:
\[ -23 = -26 + b | +26 \]
\[ 3 = b \]
so:
\[ y = -2x + 3 \]
Now just set y = 31 and solve for x.
Hope it was helpfull :)