Q
Okay, so I need to figure out how to solve this problem where I have to find the value of x in the equation 3x + 5 = 20. Let me start by recalling what I know about algebra. Alright, the goal is to isolate x, right? That means I need to get x by itself on one side of the equation.
First, the equation is 3x + 5 = 20. So, there's a 5 added to 3x. To get rid of that, I should subtract 5 from both sides. That way, I keep the equation balanced. Let me write that down: 3x + 5 - 5 = 20 - 5. Simplifying both sides, the +5 and -5 on the left cancel out, leaving 3x = 15.
Now, I have 3 times x equals 15. To solve for x, I need to do the opposite of multiplying by 3, which is dividing by 3. So, I'll divide both sides by 3. That gives me (3x)/3 = 15/3. The 3s on the left cancel out, so x = 5.
Wait, let me check if that's correct. If I plug x = 5 back into the original equation: 3*(5) + 5 = 15 + 5 = 20. Yep, that matches the right side of the equation. So, x = 5 is the right answer.
But wait, what if I made a mistake in the steps? Let me go through it again. Starting with 3x + 5 = 20. Subtract 5 from both sides: 3x = 15. Then divide by 3: x = 5. Still the same result. Hmm, seems solid.
Alternatively, could I have done it another way? Maybe by dividing first? Let's see. If I divide the entire equation by 3 first, I get x + 5/3 = 20/3. Then subtract 5/3 from both sides: x = 20/3 - 5/3 = 15/3 = 5. Oh, same answer. So either method works.
I guess the key steps are inverse operations: subtraction to undo addition, and division to undo multiplication. It's important to do the same operation to both sides to maintain equality.
Another way to think about it: What number multiplied by 3 and then added 5 gives 20? Let's break it down. If 3x is 15, then adding 5 gets to 20. So 3x must be 15, which means x is 5.
No, I don't see any errors here. The solution checks out both algebraically and by substitution. I think that's it. X equals 5 is definitely the correct answer.
To solve the equation (3x + 5 = 20) for (x), follow these steps:
Subtract 5 from both sides to isolate the term with (x):
[
3x + 5 - 5 = 20 - 5 \implies 3x = 15
]
Divide both sides by 3 to solve for (x):
[
\frac{3x}{3} = \frac{15}{3} \implies x = 5
]
https://www.18122.com/url/usdt/usdt0928.jpg
Verification:
Substitute (x = 5) back into the original equation:
[
3(5) + 5 = 15 + 5 = 20
]
The left side equals the right side, confirming the solution is correct.
Answer: (\boxed{5})
页:
[1]