29・36 The number of $x$ values that satisfy the algebraic expression
$$
\left(x^{2}-4\right)\left(x^{2}-1\right)=\left(x^{2}+3 x+2\right)\left(x^{2}-8 x+7\right)
$$

is
(A) 4 .
(B) 3 .
(C) 2 .
(D) 1 .
(1st "Five Sheep Cup" Junior High School Mathematics Competition, 1989)
[Solution] The original equation, after rearrangement and factorization, becomes
$$
5(x+2)(x+1)(x-1)=0 \text {, }
$$

Solving this, we get
$$
x= \pm 1,-2 \text {. }
$$

Therefore, the correct choice is $(B)$.