Odpowiedź:
2) 2x - 9 = 87
2x= 87 + 9
2x = 96 /: 2
x = 48
spr. 2×48-9=96-9=87
1) 4 1/3 + x = 11
x = 11 - 4 1/3
x= 6 2/3
spr. 4 1/3 + 6 2/3 = 10 3/3 = 11
3x = 14
x= 14 :3
x = 14/1 × 1/3
x= 4 2/3
spr. 3/1 × 14/3 = 42/3 = 14
1/7 x = - 4
x = - 4 : 1/7
x = - 4/1 × 7/1
x = - 28
spr.
1/7 × ( - 28/1) = - 28/7 = - 4
