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x este număr natural: a) 4(7x-2)=76 b) 5(2x-5)=(30-x)3+2

Răspuns :

a) 28x-8=76
28x=76+8
28x=84
x=84 supra 28
x=3

b) 10x-25=90-3x+2
10x-25=92-3x
10x+3x=92+25
13x=117
x=116 supra 13
x=9
a)4(7x-2)=76/:4
7x-2=19/+2
7x=21/:7
x=3

b)5(2x-5)=(30-x)3+2
10x-25=90-3x+2/+3x
10x-25+3x=92
13x-25=92/+25
13x=117/:13
x=9