Answer:
Linda: 3 ; Laura: 15
Step-by-step explanation:
Note that Linda + Laura's age is 18, and that Linda is 12 years younger than her sister.
Let "Linda" = x , "Laura" = y:
x + y = 18
x = y - 12
First, plug in y - 12 for x in the first equation:
(y - 12) + y = 18
Simplify.
2y - 12 = 18
Isolate the variable (y). Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. First add, then divide.
2y - 12 (+12) = 18 (+12)
2y = 18 + 12
2y = 30
(2y)/2 = (30)/2
y = 30/2
y = 15
Next, plug in 15 for y in the second equation (the other equation would work too).
x = y - 12
x = (15) - 12
x = 3
Linda's age is 3, Laura's age is 15.
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