Converting -4 to polar form gives
.
Then the 4th roots of -4 would be the numbers

where <em>k</em> is taken from {0, 1, 2, 3}.
So we have




15a - 54 = -9. Add 54 to each side.
15a = 45. Divide each side by 15.
a = 3
I’m pretty sure if I’m not wrong it’s 42
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