Question

If x³ + y³ + z³ = 49 and x + y + z = 1, find the value
of xy + y2 + zx - xyz.​

Answer 1

Answer:

answer: -16

Step-by-step explanation:

Given: x^3+y^3+z^3=49------(1) and

x+y+z=1------(2)

squaring on both sides of (1) provides

x^2+y^2+z^2= 1 - 2(xy+yz+xz)-------(3)

we know that

x^3+y^3+z^3-3xyz

=(x+y+z) [(x^2+y^2+z^2)-(xy+yz+xz)]------(4)

substitute values of (1), (2) and (3) in equation (4)

we get

xy+yz+xz - xyz = -16