Answer:
-70x + 21
Step-by-step explanation:
1-8(10x-3)
-7(10x-3)
Use distributive property
-70x + 21
(This is how we learned to do it in my school)
There are many possible factors:

Hope this helps!!
Answer: a=25
Explanation: I am assuming you are looking for “a” so if you heard the method of 45, 45, 90 it helps you solve it. So by the 45 being across from 25 makes the 45 across a 25 as well, hope this was what you were looking for…