Respuesta :

y=ax+b
for x=7, y=2
7a+b=2

for x=2, y=12
2a+b=12

7a-2a+b-b=2-12
5a= -10
a= -10/5
a=-2
2a+b=12
2*(-2)+b=12
-4+b=12
b=12+4
b=16
y=-2x+16

The straight answer:

y = -2x + 16

The answer below me is very detailed but doesn't show the answer clearly, so I helped.