plz neeed help with this If a line passes through the points (-2, -4) and (3, -1), the equation of the line is y + 4 = 3/5(x + _____).
plz neeed help with this If a line passes through the points (-2, -4) and (3, -1), the equation of the line is y + 4 = 3/5(x + _____).
can u help with this problem also Yfrog Image : yfrog.com/j9math14p
Ok, first, the equation of the line should be of the form $\displaystyle y=mx+b$ where m is slope and given by $\displaystyle m=\frac{y_2-y_1}{x_2-x_1} = \frac{-1-(-4)}{3-(-2)} = \frac{3}{5}$.
Hence, $\displaystyle y=\frac{3}{5}x+b$. Still need to find b.
the point (-2,-4) belongs to the lines, hence: $\displaystyle -4=\frac{3}{5}\times (-2)+b$, therefore: $\displaystyle b = -4+\frac{6}{4} = -4+\frac{3}{2}$.
Hence, $\displaystyle y=\frac{3}{5}x-4+\frac{3}{2}$.
So, $\displaystyle y+4=\frac{3}{5}x+\frac{3}{2} = \frac{3}{5}(x+\frac{3/2}{3/5}) = \frac{3}{5}(x+\frac{5}{2}) $.
$\displaystyle \frac{5}{2}$ is the answer you need.
Hi daniel323,
Are you familiar with the 'point-slope' form of a linear equation:
$\displaystyle y-y_1=m(x-x_1)$
Find your slope, which is already given to you as $\displaystyle \frac{3}{5}$
Use (-2, -4) as $\displaystyle (x_1, y_1)$ and the equation:
$\displaystyle y-y_1=m(x-x_1)$
And fill in the blank: $\displaystyle y-(-4)=\frac{3}{5}(x-(-2))\Longrightarrow \boxed{y+4=\frac{3}{5}(x+{\color{red}2})}$
2 is the answer you need.
I know the OP said this problem is already solved, but I'd just like to point out that there is an error here, there was a (6/4) where there should have been a (6/5), and the value for b is wrong.
Using point-slope equation, once you verify that the slope is (3/5), you can immediately see that the answer is 2.
Edit: Ah, masters beat me to it.