2 16/99 as decimal should be:
2 + (16/99) = 2 +0.17 = 2.17
(f+g)(x) = f(x) + g(x)
(f+g)(x) = [ f(x) ] + [ g(x) ]
(f+g)(x) = [ 3x-2 ] + [ 2x+1 ]
(f+g)(x) = (3x+2x) + (-2+1)
(f+g)(x) = 5x - 1
Answer is choice B
Lets call x the amount of 18% solution and y the amount of 40% solution, and write as equations the info of the problem:
18x + 40y = 10(20)
x + y = 10
lets multiply the second equation by -18 and add to the first:
18x + 40y = 200
-18x -<span> 18y = -180
</span>----------------------
0 + 22y = 20
y = 20/22 = 10/11
and substitute in the original equation:
x <span>+ y = 10
</span>x = 10 - y
x = 10 - 10/11
x = 110/11 - 10/11
x = 100/11
so they have to use 100/11 liters of 18% solution and 10/11 liters of 40% solution
(x-1)^2=9 <=> x-1=3 <=> x=4
1/3 is the correct answer simplified
