Question 896733
let g = girl's present age
let b = brother's age
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Write an equation for each statement
:
 the sum of the ages of the girl and brother is 26 years.
g + b = 26
:
 3 years ago her age was four time the age of her brother.
g - 3 = 4(b-3)
g - 3 = 4b - 12
g = 4b - 12 + 3
g = 4b - 9
Arrange equation for elimination
g - 4b = -9
Subtract above from the 1st equation
g + b = 26
g - 4b = -9
-------------Subtraction eliminates g, find b
0 + 5b = 35
b = 35/5
b = 7 yrs is brother's present age
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I'll let you find the girl's age; (g + 7 = 26)
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Check your solutions in the 2nd statement