Most quadratic functions(which is what you have there, to a degree of 2) are solved using factoring and the zero product law. If you can not factor then you have to use the quadratic formula or graph it. However this one can be factored.
It's pretty simple to just factor it by inspection but I use the chart method, if you know decomposition that works as well.
Factoring gives us,

Then you set each factor to 0 and solve for x,



And the second one,


The solutions to this equation are
x = -1/2, 3
4+1.5+.5= 6 cups
6 cups = 1.42 liters
Closest measurement is 1.42L
A^2 + b^2 = c^2
20^2 = 400
52^2 = 2704
400 + b^2 = 2704
2704 - 400 = 2304
So you need the square root of 2304 which is 48 so the length of the other leg is 48 ft.
First 4/7 times 7/11 and plus 5,the result of 4/7 times 7/11 equal 4/11,AND THEN 4/11 PLUS 5 EQUAL 5 AND 4/11