In solving the equation (x-1)(x+2)=30. Eric stated that the solution would be
x-1=30¨T¡úx=31 or(x-2)¨T30¨T¡úx=32 However, at least on of these solutions fails to work when subsitituted back into the orignal equation. Why is that? Please help Eric to understand better, solve the problem yourself, and explain your reasoning.
I cannot interpret your T¡ú symbol.
x^2 +x -2 -30 = 0
x^2 +x -32 = 0
Use the quadratic equation to solve.
x = [-1 +/-sqrt129]/2 = 5.1789 or -6.1789