There's no diagram here so I can't be specific, but I've attached an image.
The correct answer is A.) { - 0.79 ; 1.08 }, because
<span><span> <span>For </span><span>ax^2 + bx + c = 0</span><span>, the value of </span>x<span> is given by:</span></span> <span> ;
a = - 7 ; b = 2 ; c = 6 ;
b^2 - 4ac = 4 + 168 = 172 ; </span></span>

≈ 13.11 ;<span><span>
x 1 = ( - 2 + 13.11 ) / (- 14) = 11.11 / ( - 14 ) </span></span>≈<span><span> -0.79 ;
x = 2 = ( - 2 - 13.11 ) / ( - 14 ) = (-15.11) / (- 14 ) </span></span>≈ 1.08 ;<span><span>
</span></span>
Think of the 13-ft length of the ladder as the hypotenuse of a right triangle. Represent the horiz. distance from foot of ladder to base of tree by x, or 5 ft.
Represent the vert. dist. from base of tree to top of ladder by y, which is unknown.
Then (13 ft)^2 = (5 ft)^2 + y^2, or
169 ft^2 = 25 ft^2 + y^2. This simplifies to y^2 = 144. Thus y = + 12 feeet.
Note: Please pay attention to your spelling: "lader i up agenst a tree" should be "the top of a 13-ft ladder is placed against a tree."
1. 5x + 6 = 2 + 3x
-3x. - 3x
-------------------------
2x + 6 = 2
- 6. - 6
-------------------------
2x = -4
---- -----
2. 2
x = -2
2. 2(6 -2y) = -1(4y-9)
12 -4y = -4y + 9
+4y. +4y
----------------------------
.12 /=\ 9
No solution
3. 2z-6 = 2(z+2) + 10
2z -6 = 2z + 4 + 10
2z -6 = 2z +14
-2z. -2z
-6 /=\ 14
No solution.