how many cups of 25% soap solution must be added to 12 cups of 50% soap solution to result in a mixture that is 40% soap solution

p> q if you calculate p is100 q is 79

12/11c

or

12

c

11

the reason why your question keeps getting deleted because this is not a school related question : )

i will answer your question though.

i never tried church's

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.