When the solution of x2 + 9x − 9 is expressed as negative 9 plus or minus the square root of r, all over 2, what is the value of r? x equals negative b plus or minus the square root of b squared minus 4 times a times c, all over 2 times a 117 54 45 9

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

1 mph

step-by-step explanation:

if the question is asking how much does she drive per mile then,

13 / 13 = 1 mph

add them

step-by-step explanation:

idk you did not give the options or numbers so you cant solve it