Die korrekte Antwort lautet:
-49 : ( - 7 ) = 7

$(49-\left(35+59\right))·10$

= $\left(49-35-59\right)·10$

= $-45·10$

= $-450$

$2\cdot {\left(-3\right)}^2-{\left(-5\right)}^2$

= $2\cdot 9-25$

= $18-25$

= $-7$