Răspuns :
A)2x +5=9/ 2x=4. /x=2. /B)2x=36 / x=18 /c) 10x=40 /x=10. :d)21x=42 /x=2.
a) 2x+5=9 2x=9-5 2x=4 x=4/2 x=2 ,, b) 2x-9=27 2x=27+9 2x=36 x=36/2 x=18 ,, c) 10x-25=15 10x=15+25 10x=40 x=40/10 x=4 d) 21x-12=30 21x=30+12 21x=42 x=42/21 x=2