Question

vreau numai rezolvarile exercitiilor incercuite dau 20 puncte

Answer 1

26. 17=(-1)·(-17)
27. -15=(-1)·(-3)·(-5)
28. a·b·c=91=1·7·13=1·1·91
1+7+13=21
1+(-7)+(-13)=-19
(-1)+7+(-13)=-7
(-1)+(-7)+13=5

(-1)+(-1)+91=89
(-1)+1+(-91)=-91
1+1+91=93

29. x=?, y=? x, y cifre
13035=5·2607=5·3·869=3·5·11·79=3·79·5·11=237·55
-13035=237·(-55)
x=7, y=5
alt mod
23x·(-5y)=(230+x)(-50-y)=-(230+x)(50+y)=-(11500+230y+50x+xy)
-13035=-(11500+230y+50x+xy)
11500+230y+50x+xy=13035 |-11500
230y+50x+xy=1535
10(23·y+5·x)+xy=1535

23y+5x=153
xy=5
y=1, x=5  nu coresp
y=5, x=1 nu coresp
23y+5x=152
xy=15
y=3, x=5 nu coresp
y=5, x=3 nu coresp
23y+5x=151
xy=25
x=y=5 nu coresp
23y+5x=150
xy=35=7·5
x=7, y=5 SOLUTIE
23y+5x=149
xy=45=5·9 nu coresp
23y+5x=148
xy=55=5·11 nu mai sunt cifre

Solutia este x=7, y=5
verif 237·(-55)=-13035