Simplify the radicand by breaking the radicand up into a product of known factors.
Answer: -20<span>√7
</span>
yes I know but will not give answer because you have not say that
So, we know the center is at -3,-1, ok
hmmm what's the radius anyway? well, we know that there's a point at 1,2 that is on the circle's path...hmmmm what's the distance from the center to that point? well, is the radius, let's check then.
![\bf \textit{distance between 2 points}\\ \quad \\ \begin{array}{lllll} &x_1&y_1&x_2&y_2\\ % (a,b) &({{ -3}}\quad ,&{{ -1}})\quad % (c,d) &({{ 1}}\quad ,&{{ 2}}) \end{array}\qquad % distance value d = \sqrt{({{ x_2}}-{{ x_1}})^2 + ({{ y_2}}-{{ y_1}})^2} \\\\\\ r=\sqrt{[1-(-3)]^2+[2-(-1)]^2}\implies r=\sqrt{(1+3)^2+(2+1)^2} \\\\\\ r=\sqrt{16+9}\implies r=\sqrt{25}\implies r=5](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bdistance%20between%202%20points%7D%5C%5C%20%5Cquad%20%5C%5C%0A%5Cbegin%7Barray%7D%7Blllll%7D%0A%26x_1%26y_1%26x_2%26y_2%5C%5C%0A%25%20%20%28a%2Cb%29%0A%26%28%7B%7B%20-3%7D%7D%5Cquad%20%2C%26%7B%7B%20-1%7D%7D%29%5Cquad%20%0A%25%20%20%28c%2Cd%29%0A%26%28%7B%7B%201%7D%7D%5Cquad%20%2C%26%7B%7B%202%7D%7D%29%0A%5Cend%7Barray%7D%5Cqquad%20%0A%25%20%20distance%20value%0Ad%20%3D%20%5Csqrt%7B%28%7B%7B%20x_2%7D%7D-%7B%7B%20x_1%7D%7D%29%5E2%20%2B%20%28%7B%7B%20y_2%7D%7D-%7B%7B%20y_1%7D%7D%29%5E2%7D%0A%5C%5C%5C%5C%5C%5C%0Ar%3D%5Csqrt%7B%5B1-%28-3%29%5D%5E2%2B%5B2-%28-1%29%5D%5E2%7D%5Cimplies%20r%3D%5Csqrt%7B%281%2B3%29%5E2%2B%282%2B1%29%5E2%7D%0A%5C%5C%5C%5C%5C%5C%0Ar%3D%5Csqrt%7B16%2B9%7D%5Cimplies%20r%3D%5Csqrt%7B25%7D%5Cimplies%20r%3D5)
so, what's the equation of a circle with center at -3, -1 and a radius of 5?
Answer:
x = 7000
y = 5600
(7000, 5600)
Step-by-step explanation:
To solve the system of equations means to find the point of intersection (graphically). You are finding what value of 'x' and what value of 'y' fits both equations.
x = y + 1400
0.08x + 0.05y = 840
We can solve using the method <u>substitution</u>, where you replace a variable in one equation with an equivalent expression.
<u>Since "x" is y + 1400, we can replace "x" in the second equation.</u>
0.08x + 0.05y = 840
0.08(y + 1400) + 0.05y = 840
Distribute over brackets by multiplying 0.08 with y, then 0.08 with 1400.
0.08y + 112 + 0.05y = 840 Collect like terms (with "y" variable)
112 + 0.13y = 840
Now isolate "y" in the simplified equation.
112 - 112 + 0.13y = 840 - 112 Subtract 112 from both sides
0.13y = 728
0.13y/0.13 = 728/0.13 Divide both sides by 0.13
y = 5600 Solved for y
We can substitute "y" with 5600 in any other equation that has "x".
x = y + 1400
x = 5600 + 1400 Add
x = 7000 Solved for x
You may express the answer as a coordinate, or an ordered pair (x, y).
The solution is (7000, 5600).