#1. I'd say elimination, since you already have 7x and -7x, so if you add the equations, the x's will be easily eliminated. #2. Did you actually test your answer to see whether it satisfied the equations? From #1, if you add the equations, you get 3y=3, or y=1. In fact...
y = x(-.000475x+.851) y=0 at x=0,1791 The vertex is midway between the roots So, at x=896, y=381 The length of the bridge is the distance between the roots. (assuming the bridge just touches the river banks at the water's edge -- not too likely in the real world)
y = x^2+4x-3 complete the square: add and subtract 4 y = x^2+4x+4 - 3 - 4 y = (x+2)^2 - 7
as usual, draw a diagram. (a) x^2 + 100^2 = 250^2 (b) 25^2 + x^2 = 250^2 (c) 25^2 + 50^2 = x^2
AB^2 = (-3-2)^2 + (6-3)^2 = 25+9 = 34 AC^2 = (-4-2)^2 + (-3-3)^2 = 36+36 + 72 BC^2 = (-4+3)^2 + (-3-6)^2 = 1+81 = 82 take square root to get the actual side lengths. If ABC is a right triangle, we'd need 34+72=82, but it does not.
Math - incomplete
sorry - what's the line of reflection?
G(x) = F(x)+6 = -6x-10+6 = -6x-4
if there are x bags of flour, then 2(x+3) + 5x = 48
since consecutive angles total 180, the angles are 60 and 120 Now draw a diagram and I'm sure you will see all the 30-60-90 right triangles in there.