
Tony H. answered 09/26/18
Tutor
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Experienced Algebra Tutor
"The sum of a number and 3" is "x+3"
Write the problem as a "mathematical sentence" - convert each phrase into the corresponding part of the equation:
10 - (x+3) = 5
Now solve with algebra:
10 - x -3 = 5
7 - x = 5
7 - 5 = x
2 = x
x = 2