Step-by-step explanation:
1. you set each expression equal to 0.
x-7=0 and x+3=0
2. Next you need to get the variable by itself so you would add 7 to both sides on the first equation and subtract 3 from both sides for the second one.
3. So your answers would be x=7 and x=-3. Those are the zeros.
40 Why? 80%x X=50 or 80/100x X=50
First you had to expanded form.


Finally you can also add by similar to elements.


Final answer: 
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie