The answer is -3 because of the order of operations PEMDAS (parenthesis, exponent, multiplication/division, addition/subtraction)
Therefore, you would multiply the two numbers inside the parenthesis first, which would give you 15-18, and from there you can subtract 18 from 15 which would give you -3.
Let the age of devaughn be x and Sydney be y. Then,x+y=45 x+5=y y=x+5 here, put y=x+y in x+y=45 then, x+y=45 x+x+5=45 2x=40 x=20 now, y=x+5 y=20+5 y=25
