to go for the answer, let’s just get to work on the other answer choices.
We’ll try (C) next. If the bakery baked 140 cupcakes on Tuesday, they sold 85% of 140, or 119. Is there
anything wrong with selling 119 cupcakes? No! Since the bakery sold only whole cupcakes, you can
select (C).
Here’s another example:
7.For what value of x is |2x + 3| + 5 = 0 ?A) –4
B) 0
C) 4
D) There is no such value of x.Here’s How to Crack It
Although we covered it in the last chapter, solving algebraically on an absolute value question can be
treacherous: There are so many ways to go wrong with those signs! Luckily, this absolute value question
comes complete with answer choices, so we can simply plug in the answers to get a solution.
Let’s start with (C). When you put 4 in for x, you get |2(4) + 3| + 5 = 0, or 16 = 0. This is clearly not true,
so cross off (C) and move on to (B). If x is 0, then the original equation says |2(0) + 3 | + 5 = 0 or 8 = 0,
so you can eliminate (B), too. Let’s try (A). |2(–4) + 3 | + 5 = 0 could be rewritten as |–8 + 3 | + 5 = 0, or
|–5| + 5 = 0. As long as you remember that the absolute value of a number is always positive, it is clear
that this gives you 5 + 5 = 0. Since this is also clearly untrue, eliminate (A), and choose (D). Apparently,
there is no such value of x!
Hey, Smarty!
If you think you can
improve your SAT Math
score without learning
to plug in, you’re in for
an unpleasant surprise.
Seriously, this technique
works. Just bear in mind
that this is a multiple-
choice test; the correct
answers are already right
there on the page.Solving Rational Equations
A rational equation is basically an equation in which one (or more) of the terms is a fractional one.