now, bear in mind that all these ones are lines, and to graph a line all you need is two points, so let's pick a couple of random values for say "x" and let's see what we get for "y" and that's our x,y point.
3)
![9x+4y=-16\implies \stackrel{\textit{using x = 0}~\hfill }{9(0)+4y=-16}\implies 4y=-16 \\\\\\ y=\cfrac{-16}{4}\implies y=-4~\hspace{10em}(0~~,~~-4) \\\\[-0.35em] ~\dotfill\\\\ 9x+4y=-16\implies \stackrel{\textit{using x = -4}~\hfill }{9(-4)+4y=-16}\implies -36+4y=-16 \\\\\\ 4y=20\implies y = \cfrac{20}{4}\implies y = 5~\hspace{10em}(-4~~,~~5)](https://tex.z-dn.net/?f=9x%2B4y%3D-16%5Cimplies%20%5Cstackrel%7B%5Ctextit%7Busing%20x%20%3D%200%7D~%5Chfill%20%7D%7B9%280%29%2B4y%3D-16%7D%5Cimplies%204y%3D-16%20%5C%5C%5C%5C%5C%5C%20y%3D%5Ccfrac%7B-16%7D%7B4%7D%5Cimplies%20y%3D-4~%5Chspace%7B10em%7D%280~~%2C~~-4%29%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%209x%2B4y%3D-16%5Cimplies%20%5Cstackrel%7B%5Ctextit%7Busing%20x%20%3D%20-4%7D~%5Chfill%20%7D%7B9%28-4%29%2B4y%3D-16%7D%5Cimplies%20-36%2B4y%3D-16%20%5C%5C%5C%5C%5C%5C%204y%3D20%5Cimplies%20y%20%3D%20%5Ccfrac%7B20%7D%7B4%7D%5Cimplies%20y%20%3D%205~%5Chspace%7B10em%7D%28-4~~%2C~~5%29)
check the red line in the picture below.
4)

check the blue line in the picture below.
54 : 18 = 6 : 2
18 x 3 = 54
2 x 3 = 6
Answer:
(1)
compound amount = 802.5 $
invest earned = 52.5 $
Step-by-step explanation:
total amount = 10000 $
let amount x invested in ventures A and remaining (1000-x) on ventures B
now,
6x/100 +23/400(1000-x ) = 588.75
{24x+23(1000-x)}/400 =588.75
x=235500-230000
x=5500
Amount invested on A = 5500$
Amount invested on B = 4500$
(2)
principle=750$
time= 1 year
effective invest rate = 7%
a) compound amount = p(1+(r/w)^t
=750{1+(7/100)}^1
=802.5$
b) invest earned = 802.5-700 = 52.5$
Its adding 9 every time.
-3, 6, 15, 24, 33, 42, 51, 60