In Exercises 1–16, evaluate each algebraic expression for the giv...

Question

In Exercises 1–16, evaluate each algebraic expression for the given value or values of the variable(s). x^2-3(x-y), for x=8 and y=2

Accepted Answer

Welcome back. I'm so glad you're here. We are given an expression. I'll rewrite that bigger. We've got y squared minus two times parentheses Y minus X. And parentheses. And we're given values for X. X equals five and a value for Y. Y equals one. So that means anywhere we've got a Y. We can replace it. Here's one, here's one with a one. And anyway we've got an X. Here's one. We can replace that with a five. Let's go ahead and do that. So instead of y squared now we'll have one squared and bring down that minus two times parentheses instead of a Y. In there. We'll have a one minus instead of X. Will have a five. And our parentheses now all we've got left are numbers and we will start solving to find the value of this expression and we'll follow the rules from pem dose you may recall from previous lessons that Penda stands for parentheses, exponents multiplication and division from left to right and addition and subtraction from left to right. So that means we start looking at parentheses and see are there any operations happening in there? And yeah there's subtraction happening in there. So we do that work inside the parentheses first. So we'll bring down R one squared minus two and do the work inside the parentheses. Well one minus five that's negative four. And our parentheses are done. Why do we get to check them off? Because there are actually still parentheses there. Well there's no operations happening inside those parentheses. That's just a negative four and it actually means that this negative four is being multiplied by this negative two. So that's a multiplication parentheses. There were almost a multiplication. But first we have any exponents exponents and yes we do. So let's do our exponents first one squared. That's one times one that equals one. So bring down 1 -2 times negative four. And now we get to do that multiplication that we talked about. There's nothing else before the negative two times negative four. So we'll bring down our one and we've got negative two times negative four. Well that'll be a positive eight. And that's all the multiplication and division that has been happening. And now all that's left is some addition. So one plus eight that equals nine. We look at our answer choices and that matches with answer choice. D. While done will catch on the next one.

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