We read your photo as:

Given x+y+z=6, xy+yz+zx=11, and x3+y3+z3=36, find the values of x, y, z.

Mathematics

ScanSolve AI Answer

Answer

1, 2, 3

t3−6t2+11t−6=0t^3 - 6t^2 + 11t - 6 = 0

Step-by-step solution

4 steps
  1. Substitute the given values into the identity.

    The given system of equations is:

    x+y+z=6x + y + z = 6 xy+yz+zx=11xy + yz + zx = 11 x3+y3+z3=36x^3 + y^3 + z^3 = 36

    The provided identity is:

    x3+y3+z3−3xyz=(x+y+z)[(x+y+z)2−3(xy+yz+zx)]x^3 + y^3 + z^3 - 3xyz = (x + y + z)[(x + y + z)^2 - 3(xy + yz + zx)]

    Substitute the known values into the identity:

    36−3xyz=(6)[(6)2−3(11)]36 - 3xyz = (6)[(6)^2 - 3(11)]
  2. Solve for xyzxyz.

    Simplify the equation from Step 1:

    36−3xyz=6[36−33]36 - 3xyz = 6[36 - 33] 36−3xyz=6[3]36 - 3xyz = 6[3] 36−3xyz=1836 - 3xyz = 18

    Subtract 36 from both sides:

    −3xyz=18−36-3xyz = 18 - 36 −3xyz=−18-3xyz = -18

    Divide by -3:

    xyz=−18−3xyz = \frac{-18}{-3} xyz=6xyz = 6
  3. Form the cubic polynomial.

    For a cubic polynomial with roots x,y,zx, y, z, the general form is:

    P(t)=t3−(x+y+z)t2+(xy+yz+zx)t−xyz=0P(t) = t^3 - (x+y+z)t^2 + (xy+yz+zx)t - xyz = 0

    Using the values we have:
    x+y+z=6x+y+z = 6
    xy+yz+zx=11xy+yz+zx = 11
    xyz=6xyz = 6
    Substitute these values into the polynomial form:

    P(t)=t3−6t2+11t−6=0P(t) = t^3 - 6t^2 + 11t - 6 = 0
  4. Find the roots of the polynomial to determine $x, y, z$.

    We need to find the roots of t3−6t2+11t−6=0t^3 - 6t^2 + 11t - 6 = 0.
    By testing integer divisors of the constant term -6 (i.e., ±1,±2,±3,±6\pm 1, \pm 2, \pm 3, \pm 6):
    For t=1t=1: 13−6(1)2+11(1)−6=1−6+11−6=01^3 - 6(1)^2 + 11(1) - 6 = 1 - 6 + 11 - 6 = 0. So t=1t=1 is a root.
    Since t=1t=1 is a root, (t−1)(t-1) is a factor of the polynomial. We can perform polynomial division or synthetic division.
    Using synthetic division with root 1:

    1 | 1  -6   11  -6
      |    1   -5    6
      -----------------
        1  -5    6    0
    

    The quotient is t2−5t+6t^2 - 5t + 6.
    Now, we solve the quadratic equation t2−5t+6=0t^2 - 5t + 6 = 0.
    This factors as (t−2)(t−3)=0(t-2)(t-3) = 0.
    The roots are t=2t=2 and t=3t=3.
    Thus, the roots of the polynomial are 1,2,31, 2, 3.

    The real numbers x,y,zx, y, z are the roots of this polynomial. Since the system is symmetric, the values of x,y,zx, y, z are 1,2,31, 2, 3 in any order.

    The values for x,y,zx, y, z are 1,2,3\boxed{1, 2, 3}.
    The cubic polynomial is t3−6t2+11t−6=0\boxed{t^3 - 6t^2 + 11t - 6 = 0}.

Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question