A slope would be = (y2-y1)/ (x2-x1).
Enter the digits to get = (2-5)/(9-2)
Would give you = -3/7
A slope intersect equation would be y= mx+b, so y=-3/7x+b.
To solve for b you would take -3/7 and multiply by two as 5=(-3/7)*2+b, giving you 5=(6/7)+b. After solving that equation you get 5+6/7=b solve that and then you get 41/7=b.
Plug them all in and you get y=-3/7x+ 41/7 as the final answer.
Im not the best in algebra but I hope this helps.
Work:
= (2-5)/(9-2)
= -3/7
y=-3/7x+b
5=(-3/7)*2+b
5=(6/7)+b
5+6/7=b
41/7=b
y=-3/7x+ 41/7 (final answer)