The answer is 10x^4 - 2x^3
I solved it on a piece of paper. I can not answer why I got the same answer, but I hope my method helped
Answer:
there are two answers
Step-by-step explanation:
Exact form T=-2/3
Decimal form T=0.666666 and so on
Hope this helps :)

so.. as you can see, we use the decimal notation for the percentages... 65% is just 65/100 and 50% is just 50/100 and so on
so.. whatever the salted amounts are, we know they'll add up to (x+175)(0.50)
thus (0.30x) + (175)(0.65) = (x+175)(0.50)
solve for "x"