10x^4+7x^3-12x^2
.factor the polynomial completely
.set each of the factors equal to 0
.solve each of those equations for x

10x^4+ 7x^3-12x^2
= x^2(10x^2+ 7x- 12)
= x^2(10x^2 -8x+ 15x -12)
= x^2[ 2x(5x-4)+ 3(5x-4)]
= x^2(5x-4)(2x+3)

x^2(5x-4)(2x+3)= 0
⇒ x= 0
or 5x-4= 0
or 2x+3= 0
⇒ x= 0
or x= 4/5
or x= -3/2

The final answer is x= 0 or x= 4/5 or x= -3/2~

Yes. there is a constant ratio of number of calories to gram of protein.12/3=24/4=32/8=44/11=4