Answer:
20.3 units
Step-by-step explanation:
AB/CB = BD/AB
9/CB = 4/9
CB = 9×9/4
CB = 81/4 = 20¼ units
20.25 (20.3 units correct to 1 dp)
If it doesn't matter whether the points are integers or not you can just pick a number for either y or x and solve for the other variable. For example, if you pick 3 to be your x, plug it in and then solve for y. Start out with:

Plug in 3 for x:

. Then,

. Subtract 21 from both sides and then divide by -3 on both sides. You end up with y=-7 so one of your points is (3, -7)
I don't get you but if you transform the equation to it's standard form, it will be
3x+4y=4
First, Multiply each term by 4:
y(4)=-3x/4(4)+1(4)
4y=-12x/4+4
4y=-3x+4
Now add 3x to both sides of the equation:
4y+3x=-3x+3x+4
3x+4y=0+4
3x+4y=4
Answer:
(2,-4)
Step-by-step explanation:
(2,4) is located in Quadrent I (+,+), if you reflect over the x-axis, it would be in Quadrent IV (+,-).
if you dont understand I suggest you draw a coordinate plane on a graphing notebook.