I NEED HELP what is the side length of cube A?

Plz i want answer and i would appreciate it is is a b c or d

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test

Find the number of real number solutions for the equation. x2 + 5x + 7 = 0 0 cannot be determined 1 2