There are two triangles here: ABC and ADF. These triangles are similar, and thus proportional. So, we can set up a proportion between the left side of each triangle and the base of each triangle.
AB / AD = BC / DE
4 / (4 + BD) = 5 / 9
---AD is made up of AB and DB. We know AB, but not BD, so we need to find its value to find the length of AD.
5(4 + BD) = 9 x 4
20 + 5BD = 36
5BD = 16
BD = 3.2
AD = AB + BD
AD = 4 + 3.2
AD = 7.2
Hope this helps!
The hundreds digit is twice as large as the ones digit. 3 doubled is 6, 6 doubled is 12, and 9 doubled is 18. Since 6 is the only option that is one digit, the hundreds digit must be 6 and the ones digit must be 3. The tens digit is five less than the hundreds digit.
Firstly, let's convert 10x + 2y = -2 to slope-intercept form (y = mx + b):
10x + 2y = -2
2y = -10x - 2
y = -5x - 2/5
The slope is -5. Parallel lines have the same slope; the question provides the y-int (12), so our equation is:
y = -5x + 12
Hope this helps.
