1 - Step Equations - Video 1 of 4
Math
Solving 1-step Equations
High class, this is miss champagne, and I am going to teach you how to solve one-step equations. The first equation that we have is 9 O 5 equals D plus three, 38. And we have to figure out what the letter D stands for. Now remember from elementary school, if we are going in this direction from the plus sign to the equal sign. From the plus sign to the equal sign, we are adding. We can also work from the equal sign backwards. And instead of adding, that means that we will be what is backwards of the opposite of adding, correct, subtracting.
So we will take these two numbers and subtract them to find out what D is. So I'm going to take 9 O 5, minus three, 38. I'm going to do the opposite. Or work backwards. 5 -8, if I have 5 apples and you ask for 8, I can't give you 5 hours. So that means they need to go next door and borrow one. I see that it's a zero. My neighbor doesn't have anything that I could borrow. So then my neighbor's going to go next door and borrow one. So the 9th says, yes, you can have one. It turns into an 8. We're going to put the one right in front of that number to make it a ten. If 5 says, hey, you remember I needed to borrow one from you and Tim says, oh yeah.
Let me give you one. So this becomes a 9, and the one that he borrows goes right in front of the 5 to make it a 15. Now we have 15 -8. So you put 8 in your brain and you count 8. 9, ten, 11, 12, 13, 14, 15. So 15 -8, or 8 plus what number gives me 15, one, two, three, four, 5, 6, 7. 9 minus three. 6. 8 minus three. 5. So D is equal to 5 67. Now let's check that and make sure that we are correct. So I'm going to check it. By plugging in 5 67 for D so I have 9 O 5 equals. 5 67. Plus three 38. Does this look right? Let's add those up together and see. So 5 67 plus three 38. 8 plus 7 is 15. You put a 5, carry the one, 7, 8, 9, ten, zero, carry the one, 6, 7, 8, 9. So this is correct. So D. Is equal to 5, 67. That's an example one. Example number two