Asked by Dee
Write the quadratic equation whose roots are 2 and 1, and whose leading coefficient is 1
Not sure even how to start?
Not sure even how to start?
Answers
Answered by
Reiny
recall that if we have an equation factored equal to zero, then roots can be obtained by setting each of the factors equal to zero
e.g. if (x-6) is a factor, then x = 6 is a root
so reverse your thinking.
If the roots are 2 and 1, then the factors must have been (x-2) and (x-1)
so 1(x-2)(x-1) = 0
or if expanded:
x^2 - 3x + 2 = 0
e.g. if (x-6) is a factor, then x = 6 is a root
so reverse your thinking.
If the roots are 2 and 1, then the factors must have been (x-2) and (x-1)
so 1(x-2)(x-1) = 0
or if expanded:
x^2 - 3x + 2 = 0