D) 36x^2-81
both 36x^2 and -81 are perfect squares
difference means subtraction
Answer:
21.333 miles per gallon
Step-by-step explanation:
Answer:
13.92
Step-by-step explanation:
We can solve this using substitution.
because x-y=2.5
x=y+2.5
Now substitute x into other equation.
2(y+2.5)^2-2y=125
2y^2+10y+12.5-2y=125
2y^2+8y-112.5=0
Now comes the ugly part
y=-4+-sqrt(16+900)
y=-4+-sqrt916
y=-4+-2sqrt229
x=-1.5+-2sqrt229
