Answers edited by James W.

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• 3. Below is the decay curve for bismuth-210. What is the half-life for the radioisotope? What percent of the isotope remains after 20 days? How many half-life periods have passed after 25 days? How many days would pass while 32 grams decayed to 8 grams?
  
• Roliver is three times as old as Cerise. Three years ago, the sum of their ages was sixty-six. Find their present age?
  
• Question #9c03c
  
• How many grams of CaCl2 would you use to make 500 ml of a 6mM calcium salt solution? CaCl2=110
  
• Physics help, I'm not sure what this question is asking?
  
• How do you evaluate #\sqrt { \frac { 27} { 9} } + 5#?
  
• How do you divide #y^4-8y^3+10y^2+2y+4# by y-2 and is it a factor of the polynomial?
  
• Question #871eb
  
• What is the domain of the function g(x) = 3log2(x−1)+4 ?
  
• An isosceles triangle has sides A, B, and C with sides B and C being equal in length. If side A goes from #(1 ,4 )# to #(5 ,8 )# and the triangle's area is #27 #, what are the possible coordinates of the triangle's third corner?
  
• How do you approximate the height of the screen to the nearest tenth?
  
• How do you graph the parabola #y= - x^2 - 6x - 8# using vertex, intercepts and additional points?
  
• Question #c7208
  
• What is a radioactive isotope? Why are they radioactive?
  
• How do you solve the equation by graphing #2x^2 - 3x + 4 = 0#?
  
• A fighter jet is flying in a tight circle with a radius of 250m. It makes one complete turn in 20 seconds. How fast is the plane flying?
  
• Given the function: f (x)= -3(x+2)² + 5, how do you rewrite in standard form?
  
• How much energy is needed to heat up 10 litres of water for a bath, if the temperature of cold water is 10 degrees and the bath temperature is 38 degrees?
  
• Question #301e8
  
• Question #74e81
  
• A charge of #8 C# is passing through points A and B on a circuit. If the charge's electric potential changes from #36 J# to #6 J#, what is the voltage between points A and B?
  
• What is the magnitude of the gravitational force on Mars, with a mass of #6.34 \times 10^ 23# and a radius of #3.43 \times 10^6#m?
  
• Question #f46fd
  
• A worker’s salary is reduced by p%. By what percent would the salary have to be raised to bring it back to its original amount?
  
• 2 men and 3 women take 16 days to complete a task. How long would it take for 4 men and 6 woman?
  
• Explain why nucleus is the brain of cells ?
  
• Find the maximum height that the Pohutukawa tree is expected to reach in cm?
  
• How do you find the domain and range of #f(x) = 2 / sqrt(3x-2)#?
  
• Question #5c7c6
  
• Differentiate #cos(x^2+1)# using first principle of derivative?
  
• What is the slope-intercept form (y=mx+b) of x-y=5?
  
• Question #35aac
  
• How do you write an equation for the alpha decay of Actinium-218?