[12(.3)+x(1)]/(12+x)=.4
3.6+x=4.8+.4x
.6x=1.2
x=2 qts
(though your radiator would still be short a quart for doing so :) )
It would be false to have the same sign.
Since the first part says the value is five less then twice the square of a negative number we get the first equation as 2(-x)²-5. Then we have that -9x is equal to that previous equation. Therefore our new equation is 2(-x)²-5=-9x. We can move the nine over by adding it to both side to get 2(-x)²+9x-5=0. Then you can use any method of factoring (I prefer quadratic formula) to get your values for x. By doing so, you’ll get x=28 and x=-32.5. Since the problem said the number was negative in the first part, you know you can’t have the 28 as the answer so the right answer is -32.5.
D. John Felton kills the Duke of Beckingham
Here is some proof: https://en.wikipedia.org/wiki/John_Felton_(assassin)