document.write( "Question 1209771: Suppose the polynomial p(x)=x^3+ax^2+bc+c has the property that the mean of its zeroes, the product of its zeroes, and the sum of its coefficients are all equal. If the y-intercept of the graph of y=p(x) is 0, what is b? \n" ); document.write( "
Algebra.Com's Answer #850279 by CPhill(1987) You can put this solution on YOUR website! Let's break down this problem step-by-step:\r \n" ); document.write( "\n" ); document.write( "**1. Define the Zeros:**\r \n" ); document.write( "\n" ); document.write( "* Let the zeros of p(x) be r, s, and t.\r \n" ); document.write( "\n" ); document.write( "**2. Relationships Between Zeros and Coefficients:**\r \n" ); document.write( "\n" ); document.write( "* **Mean of Zeros:** (r + s + t) / 3 = -a / 3 \n" ); document.write( "* **Product of Zeros:** rst = -c \n" ); document.write( "* **Sum of Coefficients:** p(1) = 1 + a + b + c\r \n" ); document.write( "\n" ); document.write( "**3. Given Conditions:**\r \n" ); document.write( "\n" ); document.write( "* The mean of the zeros, the product of the zeros, and the sum of the coefficients are all equal. \n" ); document.write( "* The y-intercept of p(x) is 0. This means p(0) = 0.\r \n" ); document.write( "\n" ); document.write( "**4. Use the Y-Intercept Condition:**\r \n" ); document.write( "\n" ); document.write( "* p(0) = 0^3 + a(0)^2 + b(0) + c = 0 \n" ); document.write( "* c = 0\r \n" ); document.write( "\n" ); document.write( "**5. Apply the Equal Condition:**\r \n" ); document.write( "\n" ); document.write( "* Since c = 0, the product of the zeros is rst = -c = 0. This implies at least one of the zeros is 0. Let's say r = 0. \n" ); document.write( "* Now, we have: \n" ); document.write( " * (r + s + t) / 3 = -a / 3 \n" ); document.write( " * rst = 0 \n" ); document.write( " * 1 + a + b + c = 1 + a + b \n" ); document.write( "* Since all three are equal: \n" ); document.write( " * -a / 3 = 0 \n" ); document.write( " * 1 + a + b = 0\r \n" ); document.write( "\n" ); document.write( "**6. Solve for a and b:**\r \n" ); document.write( "\n" ); document.write( "* From -a / 3 = 0, we get a = 0. \n" ); document.write( "* Substitute a = 0 into 1 + a + b = 0: \n" ); document.write( " * 1 + 0 + b = 0 \n" ); document.write( " * b = -1\r \n" ); document.write( "\n" ); document.write( "**7. Check the Mean of Zeros:**\r \n" ); document.write( "\n" ); document.write( "* Since a = 0, the mean of the zeros is -a / 3 = 0. \n" ); document.write( "* Since r = 0, we have (0 + s + t) / 3 = 0, which means s + t = 0. \n" ); document.write( "* Also, 1 + a + b = 1 + 0 - 1 = 0, which confirms the condition.\r \n" ); document.write( "\n" ); document.write( "**Answer:**\r \n" ); document.write( "\n" ); document.write( "The value of b is -1. \n" ); document.write( " \n" ); document.write( " |