a, 27 x 39 + 27 x 63 - 2 x 27
= 27 x ( 39 + 63 - 2 )
= 27 x 100
= 2700
b, 128 x 46 + 128 x 32 + 128x 22
= 128 x ( 46 + 32 + 22 )
= 128 x 100
= 12800
c, 12 x 35 + 35 x 182 - 35 x 94
= 35 x ( 12 + 182 - 94 )
= 35 x 100
= 3500
d, 456 : 2 x 18 + 456 : 3 - 102
= 228 x 18 + 152 - 102
= 4104 + 50
= 4154
\(\text{a, 27 x 39 + 27 x 63-2 x 27 =27 x (39+63-2) = 27 x 100 =2700}\)
\(\text{b, 128 x 46 +128 x 32 +128 x 22 =128 x (46+32+22)=128 x 100=12800}\)
\(\text{c , 12 x 35 +35 x 182 -35 x 94 =35 x (12+182-94)=35 x 100=3500.}\)
\(\text{d, 456:2 x 18 +456 :3 -102 =4140+152-102=4190}\)
2,
\(45-\left(x+9\right)=6\Rightarrow45-x-9-6\Rightarrow36-x=6\Rightarrow x=30\)
\(x+7-25=13\Rightarrow x-18=13\Rightarrow x=31\)
\(450:\left(x-19\right)=50\Rightarrow x-19=9\Rightarrow x=28\)
\(4\times\left(x+41\right)=400\Rightarrow x+41=100\Rightarrow x=59\)
\(x+73-26=76\Rightarrow x+47=76\Rightarrow x=31\)