Question

2(10r-7)-2(1+10r)=-r+2r

Answer 1

r = -16

Explanation:

We will use "distributive" property and "adding like terms" concepts in solving for the unknown variable "r".

The distributive property is:

a(b+c) = ab + ac

So

2(10r-7) = 20r - 14

also

-2(1+10r) = -2 - 20r

So, our equation becomes:

`2(10r-7)-2(1+10r)=-r+2r\\20r-14-2-20r=-r+2r`

Now we add like terms and move variables (r) to one side and numbers to another. Like terms mean:

3r + 5r = (3+5)r = 8r

So, we have:

`20r-14-2-20r=-r+2r\\-16=r\\r=-16`

So,

the value of r is -16