Answer:
y = x + 53 
Explanation:
Let x be the number of flowers Jamal planted and y the number of flowers Heidi planted. 
Jamal planted 53 fewer flowers than Heidi: 
x = y - 53
Isolate the y. 
x + 53 = y (Change the - sign to + sign when switching from different sides of an equation) 
y = x + 53