"Molly had (4x + 10) dollars. Ron has (-5x + 20) dollars. How much money do they have all together?"

For this part I got -x + 30 dollars, but the problem comes when I see the next part:

"How much more money does Molly have than Ron?"

Now how to I calculate that?

To calculate how much more money Molly has than Ron, you need to subtract Ron's amount from Molly's amount.

Molly's amount is given as (4x + 10) dollars, and Ron's amount is given as (-5x + 20) dollars.

Therefore, to find out how much more money Molly has than Ron, you can subtract Ron's amount from Molly's amount:

Molly's amount - Ron's amount = (4x + 10) - (-5x + 20)

To subtract (-5x + 20), you can use the distributive property by distributing the negative sign:

Molly's amount - Ron's amount = (4x + 10) + (-1)(-5x) + (-1)(20)

Simplifying further:

Molly's amount - Ron's amount = 4x + 10 + 5x - 20

Combining like terms:

Molly's amount - Ron's amount = (4x + 5x) + (10 - 20)

Molly's amount - Ron's amount = 9x - 10

Therefore, Molly has 9x - 10 dollars more than Ron.

To calculate how much money Molly has compared to Ron, you need to subtract Ron's money from Molly's money.

First, let's simplify both expressions:
Molly's money: 4x + 10
Ron's money: -5x + 20

To find how much money Molly has compared to Ron, you subtract Ron's money from Molly's money:

(Molly's money) - (Ron's money) = (4x + 10) - (-5x + 20)

To subtract the expressions in parentheses, distribute the negative sign to every term inside the parentheses:
= 4x + 10 + 5x - 20

Combine like terms:
= (4x + 5x) + (10 - 20)
= 9x - 10

Therefore, Molly has 9x - 10 dollars more than Ron.

subtract them, just like you added:

4x + 10 - (-5x +20)

The minus turns (-5x + 20) into the opposite, or 5x - 20

4x + 10 + 5x - 20

9x - 10

-1x+30