Basic manipulating equation algebra problem?

  • Thread starter nchin
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In summary, when solving equations, it is customary to arrange the terms in decreasing degree with a positive coefficient for the leading term, but it is not wrong if this is not done. Multiplying both sides of an equation by the same number does not change the solution.
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  • #2
nchin said:
How did this:
kx^(2) = 2mgh + 2mgx

Subtract 2mgh from both sides, then subtract 2mgx from both sides

i thought it's
kx^(2) = 2mgh + 2mgx
0 = 2mgh + 2mgx - kx^(2) ?
You can do it that way, too. Now multiply every term on both sides by -1
 
  • #3
NascentOxygen said:
Subtract 2mgh from both sides, then subtract 2mgx from both sides


You can do it that way, too. Now multiply every term on both sides by -1

why do we need to mult both side by -1?
 
  • #4
nchin said:
why do we need to mult both side by -1?
That gets you the equation that you were expecting to see, but by a different route.
 
  • #5
NascentOxygen said:
That gets you the equation that you were expecting to see, but by a different route.
but what if you don't know the correct equation?

If i was doing this problem from scratch (without solution manuel)

I wouldn't have known this equation [0 = 2mgh + 2mgx - kx^(2)] was wrong because algebraically, i am correct.

is it like instincts from reading the problem to know what kind of equation to expect or something?
 
  • #6
nchin said:
How did this:
kx^(2) = 2mgh + 2mgx
become this
kx^(2) - 2mgh - 2mgx = 0
Do you want to solve for x or what?
 
  • #7
lep11 said:
Do you want to solve for x or what?

yes.
 
  • #8
nchin said:
yes.
Okay, now you got kx^(2) - 2mgh - 2mgx = 0 so you can use the quadratic formula to solve for x.
 
  • #9
nchin said:
but what if you don't know the correct equation?

If i was doing this problem from scratch (without solution manuel)

I wouldn't have known this equation [0 = 2mgh + 2mgx - kx^(2)] was wrong because algebraically, i am correct.
It's not wrong. It's perfectly correct.

In general, it is customary to arrange the terms in decreasing degree, and with the leading term having a positive coefficient, e.g., x2 - 4x + 3 = 0

But this is just for appearances (and it makes it easier to comprehend), it's not wrong if you don't do this.

Multiplying both sides does not change anything material. If you do the same thing to both sides of an equation, you change nothing.
 

1. What is the purpose of manipulating equations in algebra?

The purpose of manipulating equations in algebra is to solve for a specific variable or to simplify an equation to make it easier to solve. This is a fundamental skill in algebra that helps us understand and solve more complex equations.

2. How do you manipulate equations?

To manipulate equations, you can use various algebraic properties and operations such as addition, subtraction, multiplication, and division. You can also use the distributive property, combining like terms, and isolating variables to manipulate equations.

3. What are the steps to solving a basic manipulating equation algebra problem?

The steps to solving a basic manipulating equation algebra problem are as follows:

  • Identify the variable you need to solve for.
  • Use algebraic properties and operations to manipulate the equation.
  • Combine like terms or use the distributive property to simplify the equation.
  • Isolate the variable on one side of the equal sign.
  • Solve for the variable.

4. Can you provide an example of a basic manipulating equation algebra problem?

Example: Solve for x in the equation 3x + 7 = 22

To solve this equation, we need to isolate the variable x on one side of the equal sign. First, we subtract 7 from both sides to get 3x = 15. Then, we divide both sides by 3 to get x = 5. Therefore, the solution to this equation is x = 5.

5. How can I check if my solution to a basic manipulating equation algebra problem is correct?

To check if your solution is correct, you can substitute the value you found for the variable back into the original equation. If both sides of the equation are equal, then your solution is correct. In our previous example, we can check our solution by substituting x = 5 into the equation 3x + 7 = 22. This gives us 3(5) + 7 = 22, which simplifies to 15 + 7 = 22. Since both sides are equal, we know that our solution of x = 5 is correct.

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