Strategy #8: Make Two Expressions Or Equations Look The Same
Strategy #8: Make two expressions or equations look the same
From your algebra classes you are used to finding the value of a single variable. However, many questions on the SAT ask, instead, for the value of an expression and not necessarily for a single variable. Sometimes a question wants you to identify an equivalent expression to the one that is given.
Stack the expressions (or equations) vertically; it makes comparison easier.
Look to see if there are one or two simple manipulations you can perform on one to make it look like the other. (Sometimes, however, simply solving for the unknown is faster, especially if you are at the beginning of the test..)
It’s generally easier to make a more complicated expression look like a simpler one.
When you are given an expression to match with a more complicated one in the list of choices, use Bottoms Up! strategy. That is, see if you can transform the given to look like the expression in choice D.
Alternatively, you can use substitution to guess and check. Let a number go in for the whole expression. Pay attention to any restrictions. See substitution above.