It is answer choice B. Using the distributive property, -12x^3+15x^2-24x-6x^2+30x-42. Then combine like terms.
Since it’s vertical it would be x=-7
If his water to cement ratio is 20 to 30, this means that if he uses 20 liters of water, he'd use 30 liters of cement.
The total mixture would then be 20+30=50 liters.
and the water would be 20/50=0.4 or 40% of the total mixture.
The value of 4 in 34,258 is 4,000 times the value of 4 in 47,163 is 40,000
40,000*4,000 is 160000000