(1)计算: | - 2 | + ( - 1 ) 2 + ( - 5 ) 0 - 4 ;
(2)解方程组: x + 2 y = 9 , ① 3 x - 2 y = - 5 ⋅ ② .
计算:.
计算:(每小题8分,共16分)(1) ×÷(2) +6-2x
计算:;
计算:
.