SOLUTION: In 3 years,Carlo will be 3 times as old as his sister Daisy. A year ago, Carlo was 7 times old as Daisy. How old are they now i need a solution about "problems involving systems

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Question 806958: In 3 years,Carlo will be 3 times as old as his sister Daisy.
A year ago, Carlo was 7 times old as Daisy. How old are they now
i need a solution about "problems involving systems of linear equations".. please help me
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
c is carlo's age
d is daisy's age

c+3=3(d+3).
c-1=7(d-1), but the worded description might be ambiguous.

Organizing each equation into the same form,
c+3=3d+9
c-3d=9-3
c-3d=6
'
c-1=7d-7
c-7d=-7+1
c-7d=-7
'
The system of equations is
highlight%28c-3d=6%29
highlight%28c-7d=-7%29

Use any method you know to solve the system. You could solve each equation for c and equate those expressions to solve for d; or you could subtract one equation from the other and solve for d. You could then solve for c knowing your value for d.