E= Emma's age
emma's sister's age= e+9 (emma's age plus 9)
e+9=49
(isolate your variable)
e+9-9=49-9
e=40
Emma is 40 years old
To check: Emma's sister is 9 years older right? take emmas age 40 plus the nine more years and you still get the total of 49! hope that helps good luck
