Yes, it does.
it is because, Perimeter of square = 4 L
So, how much acid is there in 6 gallons? well is 20% acid or (20/100), so the amount of acid in it just (20/100) * 6 or 1.2, the rest is say water.
now, if we want a 90% solution, and say we add "y" gallons, how much acid is in it? well (90/100) * y, or 0.9y.
now let's add "x" gallons of pure acid, now, pure acid is just pure acid, so is 100% acid, how much acid is there in it? (100/100) * x, or 1x or just x.
we know whatever "x" and "y" amounts are, they -> x + 6 = y
and we also know that x + 1.2 = 0.9y
243 because if you divide and subtract it would culminate to the amount of people
7) Use distributive property
3x(4x⁴ - 5x)=3x*4x⁴- 3x*5x = 12x⁵ - 15x²
8) When you open parenthesis with minus sigh in front of it, you need change sings of the terms on opposite. Then find like terms.
(5x⁴-3x³+6x)-(3x³+11x²-8x)= 5x⁴-3x³+6x -3x³-11x²+8x =5x⁴-6x³ - 11x²+14x
9)(x-2)(3x-4)=x*3x-4x-6x+8=3x²-10x+8
10) (x+6)²=(x+6)(x+6)=x²+6x+6x+36=x²+12x+36
For (x+6)², you can also use the formula of the perfect square
(a+b)²=a²+2ab+b²
For (x+6)² =x²+2*x*6 +6²=x²+12x+36