
Name: Justin
Who is asking: Student
Level: Secondary
Solve the following equations for x
 x+7=10
x=
 x7=10
x=
 3x=7
x=
 x/3=10
x=
 x/2+x/2=25
x=
 5x2=3x+8
x=
 3(x+2)=4(x1)
x=
 x+3/2=2x7/7+3
x=
Hi Justin,
I like the "balance anology" for equations of this sort. In your first equation you have a balance with a "weight" of x+7 on one side and a "weight" of 10 on the other. The object is to manipulate the weights, without upsetting the balance, so that you end with only the variable x on one side and a number on the other, that is x=...
In the first problem
x + 7 = 10
if you subtract 7 from both sides, the balance is maintained and you get
x + 7  7 = 10  7
or
x = 3
You should now check to see that "x = 3" is correct. In the original equation,
x + 7 = 10,
substitute x = 3 to see if you really do have a balance. When x = 3 the left side of the equation is
x + 7 = 3 + 7 = 10
which is the same as the right side and hence x = 3 is correct.
Now try the others. If you have trouble it might help to look at my solution to
Kelley's problem.
Cheers,
Penny
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