The fence is 26*7=182 square feet. 1 gallon is enough for 350 square feet and x for 182 square feet. => x=182/350=0.52 gallons. I hope I'm right.
Pythagorean theorem a^2+b^2=c^2
2x^2 + x + 3=0 has only complex roots.
The determinant is 1-4*2*3 = -23
-23 (or any determinant) is the part under the square root sign, If that determinant is negative, knowing you cannot take the square root of a negative number, we know the answers must be complex.
The LCD here is 20. Thus, 1/4 = 5/20. The sum of 5/20 and 13/20 is 18/20, which can be reduced to 9/10.