y = mx + b
slope(m) = -1
(7,2)...x = 7 and y = 2
now we sub and find b, the y int
2 = -1(7) + b
2 = -7 + b
2 + 7 = b
9 = b
so ur equation of this line is : y = -1x + 9.....can also be written as :
y = -x + 9....or if u need it in standard form, it is : x + y = 9
