18=30-r30 solve for r
2 answers:
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Quadratic equation is 
WHEN
So, to make this true subtract 7 from each side.
The equation is now 7
- x - 7 = 0
Values for a, b, and c: a = 7, b = -1, c = -7
Plug these variables into the quadratic equation.
Square -1 to get 1 and multiply -4 x 7 x -7 to get 196.
Multiply 2 x -7 to get -14, the denominator, and add 1 to 196.
Since 197 is not a square number, and I don't know if you want to leave it in radical form or not, I will just because it's easier to understand.
Hope this helps!
So, to make this true subtract 7 from each side.
The equation is now 7
Values for a, b, and c: a = 7, b = -1, c = -7
Plug these variables into the quadratic equation.
Square -1 to get 1 and multiply -4 x 7 x -7 to get 196.
Multiply 2 x -7 to get -14, the denominator, and add 1 to 196.
Since 197 is not a square number, and I don't know if you want to leave it in radical form or not, I will just because it's easier to understand.
Hope this helps!
Answer:
28 gallons
Step-by-step explanation:
We are given that a sports car gets 14mpg in city driving and 19mpg for highway.
The model G=
Where G=Amount of gasoline used (in gal) for c miles driven in the city and h miles driven on the high way.
Amount of gas used in 14 miles car in the city driving=1 gal
Amount of gas used in 1 mile car in the city driving=
Amount of gas used in c miles car in the city driving = gal
Similarly, for car driving on highway
Amount of gas used in h miles for car driving on highway=
c=98 miles in the city
h=399 miles on the highway
We have to find the amount of gas used required to derive 98 miles in the city and 399 miles on the highway.
Substitute the value of c and h in the given expression
Then, G=
Hence, the amount of gas required to derive 98 miles in the city and 399 miles on the highway=28 gallons