You do it just exactly as the question says: Take one choice,
substitute it in place of 't' in the given equation, and see if the
equation becomes a true statement.
I'll do 'A' for you:
Does 't' = 8 ?
Let's see.
If it does, then (1/2) (8) - 4(2 + 8) = 20
( 4 ) - 4( 10 ) = 20
( 4 ) - 40 = 20
-36 = 20 .
Is that a true statement ? Is -36 = 20 ?
I don't think so.
=> 't' is not 8 .
'A' is not the correct choice.
Now go ahead and try 'B'.
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It might be faster and easier to just take the equation and solve it.
Then you'll know what 't' is, and you won't have to try any suggestions.
Here's the equation: (1/2) (t) - 4(2 + t) = 20
Eliminate parentheses
on the left side: 1/2 t - 8 - 4t = 20
Combine the 't's
on the left side: -3.5 t - 8 = 20
Add 8 to each side: -3.5 t = 28
Multiply each side by -1 : 3.5 t = -28
Divide each side by 3.5 : t = - 8 .
Now you can look back at the choices
and see that 'B' is the one you want.
