|y-9|=6
y-9=6
y-9=-6
y=15
y=3
So, y=15,3
well, we can say that 1 hour is 100%, what is 2/5 hr off of it in percentage?
![\begin{array}{ccll} hour&\%\\ \cline{1-2} 1 & 100\\ \frac{2}{5}& x \end{array} \implies \cfrac{1}{~~ \frac{2}{5}~~}=\cfrac{100}{x}\implies \cfrac{5}{2}=\cfrac{100}{x} \\\\\\ 5x=200\implies x=\cfrac{200}{5}\implies x=40](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Bccll%7D%20hour%26%5C%25%5C%5C%20%5Ccline%7B1-2%7D%201%20%26%20100%5C%5C%20%5Cfrac%7B2%7D%7B5%7D%26%20x%20%5Cend%7Barray%7D%20%5Cimplies%20%5Ccfrac%7B1%7D%7B~~%20%5Cfrac%7B2%7D%7B5%7D~~%7D%3D%5Ccfrac%7B100%7D%7Bx%7D%5Cimplies%20%5Ccfrac%7B5%7D%7B2%7D%3D%5Ccfrac%7B100%7D%7Bx%7D%20%5C%5C%5C%5C%5C%5C%205x%3D200%5Cimplies%20x%3D%5Ccfrac%7B200%7D%7B5%7D%5Cimplies%20x%3D40)
Do a proportion
8/100= x/70
Cross multiply and divide
70 x 8= 560
560 divided by 100= 5.6
Answer is 5.6
You also could have done .08 x 70 which is also 5.6
Hello,
x² + 5x + 6 = 0
a = 1 ; b = 5 ; c = 6
∆ = b² - 4ac = 5² - 4 × 1 × 6 = 25 - 24 = 1 > 0
2 solutions :
![x_{1} = \frac{ - b - \sqrt{\Delta} }{2a} = \frac{ - 5 - 1}{2 \times 1} = \frac{ - 6}{2} = - 3](https://tex.z-dn.net/?f=%20x_%7B1%7D%20%3D%20%20%5Cfrac%7B%20-%20b%20-%20%20%5Csqrt%7B%5CDelta%7D%20%7D%7B2a%7D%20%20%3D%20%20%5Cfrac%7B%20-%205%20-%201%7D%7B2%20%5Ctimes%201%7D%20%20%3D%20%20%5Cfrac%7B%20-%206%7D%7B2%7D%20%20%3D%20%20-%203)
![x_{2} = \frac{ - b + \sqrt{\Delta} }{2a} = \frac{ - 5 + 1}{2 \times 1} = \frac{ - 4}{2} = - 2](https://tex.z-dn.net/?f=x_%7B2%7D%20%3D%20%20%5Cfrac%7B%20-%20b%20%20%2B%20%20%20%5Csqrt%7B%5CDelta%7D%20%7D%7B2a%7D%20%20%3D%20%20%5Cfrac%7B%20-%205%20%20%2B%201%7D%7B2%20%5Ctimes%201%7D%20%20%3D%20%20%5Cfrac%7B%20-%204%7D%7B2%7D%20%20%3D%20%20-%202)
S = { -3 ; -2}
A=pi radius^2
7 is the radius
Pi7^2=153.93