Answer: y = 2x + 7
The number of squares in figure 1 is 7
The number of squares in figure 2 is 9
The number of squares in figure 3 is 11
So the pattern is 7, 9, 11
y = 2x + 7, for x >= 0
for the first figure x = 0, then y = 2(0) + 7 = 7
for the second figure x = 1, then y = 2(1) + 7 = 9
for the third figure x = 2, then y = 2(2) + 7 = 11