3*3 = 9
3*7=21
2*2*2*2*2= 32
2*2*2*7= 56
( 9 и 32 ) , ( 9 и 56 ) , ( 21 и 32 )
(х+х+4)•2=28
(2х+4)•2=28
4х+8=28
4х=28-8
4х=20
х=20:4
х=5см одна сторона
5+4=9см другая сторона
(5+9)•2=28см - периметр
1) = 6m + 3 + 4m - 7 = 10m - 4
2) = - 18n - 6 + 12n + 9 = - 6n + 3
3) = 18 - 15x - 17x + 10 = 28 - 32x
4) 14x - 21 - 6x + 12 = 8x - 9
5) = 5x - 1 - 2 + 8x = 13x - 3
6) = 6 - 2x + 15 - 3x = 21 - 5x
7) = 37 - x + 16 + 11x - 53 = 10x
137*3+48=459 (137*3=411+48=459).
804-126*4=300 (126*4=504, 804-504=300).
69:3*7= 161 (69:3=23*7=161).
25*8:10=20 (25*8=200:10=20).
400-96:6= 384 (96:6=16 400-16=384).
87*3+275= 536 (87*3=261+275=536)