I see your last line is : c(x) = 0.9(x^2-10)^2 + 101.1
Let y = x^2, then c(y) = 0.9(y-10)^2 + 101.1
Apparently, c(y) is a parabola, min is 101.1 when y = 10, max is infinity
So let x^2 = 10 -> x = sqrt(10) or -sqrt(10), min is 101.1, max is infinity
1. Angle DEF
2. Definition of congruent angles
3. The measure of angle GHI
Let the first investment be x
and second be 3000-x
so 3%of x + 4% of (3000-x) = 107
By solving x = 1300
First investment is 1300
second investment is 1700
1 kilogram = 2.2 pounds
45 kilograms = 2.2 x 45 = 99 pounds
Since 1 km = 1000 m, the lawnmowers top speed would be 8000 m/h.