Subtracting the second equation by 18 on both sides, we have xy=-18. Next, we divide both sides by x to get y=-18/x Plugging that into the first equation, we have x+2(-18/x)=9. Multiplying both sides by x, we get x^2-36=9x. After that, we subtract both sides by 9x to get x^2-9x-36=0. Finding 2 numbers that add up to -9 but multiply to -36, we do a bit of guess and check to find the answers to be -12 and 3. Factoring it, we get
x^2-12x+3x-36=x(x-12)+3(x-12)=(x+3)(x-12). To find the x values, we have to find out when 0=(x+3)(x-12). This is simple as when you multiply 0 with anything, it is 0. Therefore, x=-3 and 12. Plugging those into x=-18/y, we get x=-18/y and by multiplying y to both sides, we get xy=-18 and then we can divide both sides by x to get -18/x=y. Plugging -3 in, we get -18/-3=6 and by plugging 12 in we get -18/12=-1.5. Therefore, our points are (-3,6) and (12, -1.5)
Answer:
A clinical test on humans of a new drug is normally done in three phases. Phase I is conducted with a relatively small number of healthy volunteers. For example, a phase I test of a specific drug involved only 7 subjects.
Step-by-step explanation:
Answer: 8:9
Step-by-step explanation: Two find this answer, you need to see what will be the greatest number they can divide by (greatest common divider), it needs to be the same number for both 18 and 16. What number can go into both numbers, and is the greatest number? The answer is two, now you divide 2 by 18 and 16, so you'll get 8:9.
Hope this helps have a BLESSED and wonderful day! :-)
-Cutiepatutie
Sales tax is:
$62.80* (6/100)= $3.77
$62.80+ $3.77= $66.57
The cost of the skateboard including sales tax is $66.57~
