SOLUTION: please help me solve this equation: {{{a(3a+1)-(2a+1)(a-1)}}}
I have tried to solve it like this; {{{3a^2+1a-2a^2+2a-1a-1}}}
But according to my teacher, the answer I get, =a^2
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-> SOLUTION: please help me solve this equation: {{{a(3a+1)-(2a+1)(a-1)}}}
I have tried to solve it like this; {{{3a^2+1a-2a^2+2a-1a-1}}}
But according to my teacher, the answer I get, =a^2
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Question 1198978: please help me solve this equation:
I have tried to solve it like this;
But according to my teacher, the answer I get, =a^2+4a-1, is wrong.
I do not understand what I have done wrong. Answer by mccravyedwin(407) (Show Source):
When you got to -(2a+1)(a-1), since it is preceded by a "-",
you should have kept the "FOIL"ing process inside parentheses,
because it's easy to make a mistake to FOIL and change signs
all in one step, as you did. You forgot to change the sign of -1.
As I used to tell my students, "It's better
to get writer's cramp than to miss the problem". lol
You also made an error combining the terms +1a+2a-1a which
should have been 2a, not 4a.
Edwin
