MHB Solve linear algebra equation 2x – 1 = 9 – 3x

[gazparkin]

Hi,

Could someone help me with this question:

2x – 1 = 9 – 3x

Thank you in advance!

 

[gazparkin]

Hi,

Could someone help me with this question:

2x – 1 = 9 – 3x

Thank you in advance!

Sorry, there's another one that I'm stuck on too. Really interested to understand the working out on this.

4(3b-1)+6=5(2b+4)

 

[topsquark]

Hi,

Could someone help me with this question:

2x – 1 = 9 – 3x

Thank you in advance!

Step 1: Get all the x's on one side: Subtract 2x on both sides:
2x - 1 - 2x = 9 - 3x - 2x

-1 = 9 - 5x

Now do the same with the numbers. Can you finish?

-Dan

- - - Updated - - -

Sorry, there's another one that I'm stuck on too. Really interested to understand the working out on this.

4(3b-1)+6=5(2b+4)

Expand the parentheses:
4(3b - 1) + 6 = 5(2b + 4)

[math]4 \cdot 3b + 4 \cdot (-1) + 6 = 5 \cdot 2b + 5 \cdot 4[/math]

Now combine terms:
12b - 4 + 6 = 10b + 20

12b + 2 = 10b + 20

Now it's like your first problem. Can you finish?

-Dan

 

[gazparkin]

Step 1: Get all the x's on one side: Subtract 2x on both sides:
2x - 1 - 2x = 9 - 3x - 2x

-1 = 9 - 5x

Now do the same with the numbers. Can you finish?

-Dan

- - - Updated - - -Expand the parentheses:
4(3b - 1) + 6 = 5(2b + 4)

[math]4 \cdot 3b + 4 \cdot (-1) + 6 = 5 \cdot 2b + 5 \cdot 4[/math]

Now combine terms:
12b - 4 + 6 = 10b + 20

12b + 2 = 10b + 20

Now it's like your first problem. Can you finish?

-Dan

Thanks Dan - makes this really clear. The first one I get x=4 and the 2nd one I get b=9.

 

[topsquark]

Thanks Dan - makes this really clear. The first one I get x=4 and the 2nd one I get b=9.

The second one is okay. Let's take another look at the first one. I left off with
-1 = 9 - 5x

Now get the numbers:
-1 - 9 = 9 - 5x - 9

-10 = -5x

[math]\dfrac{-10}{-5} = \dfrac{-5x}{-5} [/math]

2 = x

-Dan