y = kx + b
(0;−8)
−8 = 0k + b
b = −8
 
(2;12)
12 = 2k − 8
2k = 12 + 8
2k = 20
k = 10
 
y = 10x − 8 − уравнение прямой.
при x = −2:
y = 10 * (−2) − 8 = −20 − 8 = −28;
при x = 4:
y = 10 * 4 − 8 = 40 − 8 = 32;
при x = 6:
y = 10 * 6 − 8 = 60 − 8 = 52.

y = kx + b
(0;5)
5 = 0k + b
b = 5
 
(10;6)
6 = 10k + 5
10k = 6 − 5
10k = 1
k = 0,1
 
y = 0,1x + 5 − уравнение прямой.
при x = −10:
y = 0,1 * (−10) + 5 = −1 + 5 = 4;
при x = 30:
y = 0,1 * 30 + 5 = 3 + 5 = 8.
при y = −15:
−15 = 0,1x + 5
−20 = 0,1x
x = −200
при y = 15:
15 = 0,1x + 5
10 = 0,1x
x = 100