
This is because



(that is, replace any instance of <em>x</em> in the definition of <em>g</em> with √<em>x</em> )
and


(replace any <em>x</em> in <em>f</em> with √<em>x</em> - 1)
Also acceptable:


(assuming <em>x</em> is not negative)
When a point divide a line segment A (x1,y1) B (x2,y2) into a ration of a:b, the coordinates of that point is x1+[a/(a+b)](x2-x1), y1+[a/(a+b)](y2-y1)
so x=0+(2/3)(6-0)=4
y=4+(2/3)(8-4)=6&2/3 (mixed number 6 and 2 over 3)
(4, 6&2/3) is the answer.
They are all even numbers
Let x=grams of 70% alloy:
0.70x+16×0.20=0.30(x+16)
0.70x=0.30x+4.8-3.2
0.40x=1.6
x=1.6/0.4=16/4=4g
4 grams of 70% alloy are needed.