Arunner warmed up for 10 minutes and then takes seven minutes to run each mile. the total time after r miles is 45 minutes how many miles are run

So our equation to find this can be represented by 7x + 10 = 45.
(x representing miles run)
Just solve for x!

Subtract the 10 from both sides, you've got
 7x = 35
And now to isolate the x, we divide both sides by 7.
Now we're left with just
x = 5!

We can check this by substituting 5 as x in our equation.
7x x 5 + 10 = 45
45 = 45
It's right!

So the runner ran 5 miles total.

Hope this helps!
If I skimmed over this too much, let me know and I'll try to explain the best that I can.