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Video: Evaluating Algebraic Expressions

Bethani Gasparine

Evaluate 4𝑦 ÷ (2𝑥 + 2), given that 𝑥 = 3 and 𝑦 = 20.

01:30

Video Transcript

Evaluate four 𝑦 divided by two 𝑥 plus two given that 𝑥 equals three and 𝑦 equals 20. Here we have our expression. We need to replace 𝑦 with 20 and replace 𝑥 with three. In order to evaluate, we must follow the order of operations. First comes parentheses. So inside our parentheses, we have two times three plus two.

The order of operations has an order: first parentheses then exponents, multiplication and division whatever comes first left or right, and then addition and subtraction whatever comes first left to right.

So as we’ve said, we need to take the parentheses and evaluate that first. So inside the parentheses, we have multiplication and addition. So we need to multiply before we add. So two times three gives us six. Now to finish what’s inside the parentheses, we need to take six and add two. And six plus two is eight. Now all that’s left is the multiplication of four and 20 and then dividing by eight. So we must multiply four times 20 first, which means we have 80 divided by eight, which equals 10. So our final answer is 10.