Answer:
YOU ADD UP ALL THE DECIMALS
Step-by-step explanation:
Let Mary Sue have m necklaces and Betty have b necklaces.
And they have 603 necklaces altogether, that is
m + b =603
And Mary Sue has 115 more necklaces than Betty, that is
m=b +115
Substituting this value in first equation we will get
b+115+b=603
Subtracting 115
2b= 488
b= 244
So Betty have 244 necklaces .
If you were to make both x's equivalent, you'd have to multiply the first equation by 2 to get rid of the coefficient, 1/2. However, you'd have to multiply 2 onto -8 as well, therefore the equation would turn into x - 16 = 18. That is not equivalent to x - 8 = 18.
