The formula of a line is:
![f(x) = kx + b](https://img.qammunity.org/2023/formulas/mathematics/high-school/zed01ukh6iwluqpfkc3tv9mu2q1wk5kg0p.png)
k — stands for tg of line angle
b — stands for the y value of a point where the line crosses y axis.
We can see 2 points:
A (1, -4)
B (3, -5)
We can make a system of equations:
![k*1+b=-4\\k*3+b=-5\\](https://img.qammunity.org/2023/formulas/mathematics/high-school/qh8y4s4tvxq9yghc5g745vp56wezmdhe0f.png)
From second equation:
![b = -5 - 3k](https://img.qammunity.org/2023/formulas/mathematics/high-school/sysacc0y739quhfef03g1tdtp985su5a48.png)
Let's put b in first equation:
![k-5-3k=-4\\-2k=1\\k=- (1)/(2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/oumh0jzav1tjzmxs4kh0d4ze4eymobqyi6.png)
Now we can find b:
![b = -5 -3*- (1)/(2)\\b = -5 + 1.5\\b = -3.5](https://img.qammunity.org/2023/formulas/mathematics/high-school/q9m7vajf0eu7aqn5sodrneb7bi6utgtqpf.png)
The answer is:
-0.5x -3.5