7. Given positive integers $x, y, z$ and real numbers $a, b, c, d$ satisfying $x \leqslant y \leqslant z, x^{a}=y^{b}=z^{c}=70^{d}, \frac{1}{a}+\frac{1}{b}+$ $\frac{1}{c}=\frac{1}{d}$, then the relationship between $x+y$ and $z$ should be $x+y$ $\qquad$ $z($ fill in “>”, “＜" or “=”).
7. $x+y=z$.
$a=d \log _{x} 70, b=d \log _{y} 70, c=d \log _{z} 70$, so $\log _{70} x y z=1, x y z=70, x=2, y=5, z=7$.