Answer: 9
Step-by-step explanation:
2X+5=3X-4
-2X. -2X
5= X-4
+4
9=X
I don't know about the first one but the second one is 34.9°. It would be that because are right angles add up to 90° and if you subract 55.1 and 90 it would equal 34.9. But this rule only works on right angles.
Let there be x quarts of the 20% salt solution, and (25 - x) quarts of the 80% salt solution.
Then the total amount of salt in the 20% portion would be 0.2x, while that from the 80% portion would be (0.8)(25 - x). This would have to total up to (0.44)(25) in the final solution, so the equation is:
0.2x + 0.8(25 - x) = (0.44)(25)
-0.6x + 20 = 11
x = 15 quarts of the 20% salt solution
25 - x = 10 quarts of the 80% salt solution
Answer:

Try to solve the similtanious equation to find the first term and the common difference, then use that information to figure out the 80th term... Update me if you need further help ...