Question

if x=(-2) then,the value of x³-x²+7 is​

Answer 1

Answer:

X^2(X-1)X(X+1) = X^2(X-1)(X-1)

Strike out the common elements on both sides. ie., X^2(X-1)

=> X(X+1) = (X-1)

=> X^2 + X = X-1

cancelling X on both sides,

=> X^2 = 1

=> X = +1 or -1

Put value of X = 1 in the equation we get,

X^3(X^2-1) = X^2(X-1)^2

= 1^3(1^2-1) = 1^2(1-1)^2

= 1^3(0) = 1^2(0)

= 0 = 0.

Put value of X = 1 in the equation we get,

X^3(X^2-1) = X^2(X-1)^2

=(-1)^3[(-1)^2-1] = (-1)^2[(-1)-1]^2

= (-1)[1-1] = 1[-2]^2

= 0 = 4.

since LHS is not equal to RHS, X cannot be -1.

Therefore, X=1

Answer 2

Answer:

-5

Step-by-step explanation:

x=-2

x³=(-2)³

x³=-8

x²=(-2)²

x²=4

=> x³-x²+7

=> (-8) - (4) + 7

=> -8 - 4 + 7

=> -12 + 7

=> -5

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