Tutor profile: Rachel F.
If we are solving for x in x - 3 = 7, why do we not subtract 3?
When we are solving a one-step equation like this one, we want to try and isolate x, or get it by itself on one side. To do that, we need to make the left side x + 0. So how to we change -3 to 0? By adding 3. And whatever we do to one side, we have to do to the other, so that the equation remains balanced. So when we add 3 to both sides of this equation, what is on the right side of the equation? x = 10. Now let's check our answer by substituting 10 for x in the original equation.
Subject: Basic Math
Why is -6 + 2 not -8?
Let's take a look at a number line. When we add numbers, we always want to move to the right on the number line. When we subtract, we always want to move left. So if we start at -6 on this number line, and move two spaces to the right, what number do we get?
For (x + 2)^2, why can't we just square the inside terms?
Remember that squaring something means to multiply a term times itself. So when we square a binomial, what we are actually multiplying is (x+2)(x+2). This creates a third term that you will not get by just squaring each part of the binomial. Let's use the distributive property/ box method/ FOIL to solve this problem.
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