Помогите 1,3,4 задание

Question

Помогите
1,3,4 задание

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Answer 1

1) a-b-c+d
-l+a-b+k
-t-a+c-t-k
-b-a-c+f+k+n-l
3) 
-1.4+3.6=5,7-x
2.2=5.7-x
x=5.7-2.2
x=3.5

17/6+y-7=-17/2
y=-17/2-17/6+7
y= -17*3/6 - 17/6+ 7*6/6
y= -51/6-17/6+42/6
y= -26/6
y= -13/3
4) -3a+24-6a+12= -9a+38= -9*4+38= -36+38= 2