The greatest common factor of both x^4 and x^3 would be x^3, since the largest number of X variables that you can evenly take out between both terms is x^3 or x cubed.
Answer:
1.2
Step-by-step explanation:
First, you cancel out
to become 
Then that becomes 
Now, you convert the element to a decimal form to be 
Finally, you subtract them (because a negative plus a positive is subtraction) to get the final answer of 1.2
Hope this helps!
Use the Pythagorean theorem to solve this problem. So, 81+x^2=1681. ( Pythagorean theorem: a^2+b^2=c^2). x^2=1600. x=40.