Question

Afla termenul necunoscut:

a) d-2×(480×2-90:10)+5=75

b)100-[36+6×9-(a:3+15)]:3=76

Answer 1

a)

d - 2 × ( 480 × 2 - 90 : 10 ) + 5 = 75

d - 2 × ( 960 - 9 ) + 5 = 75

d - 2 × 951 + 5 = 75

d - 1902 + 5 = 75

d - 1902 = 75 - 5

d - 1902 = 70

d = 70 + 1902

d = 1972

b)

100 - [ 36 + 6 × 9 - ( a : 3 + 15 ) ] : 3 = 76

100 - [ 36 + 54 - ( a : 3 + 15 ) ] : 3 = 76

100 - [ 90 - ( a : 3 + 15 ) ] : 3 = 76

[ 90 - ( a : 3 + 15 ) ] : 3 = 100 - 76

[ 90 - ( a : 3 + 15 ) ] : 3 = 24

90 - ( a : 3 + 15 ) = 24 × 3

90 - ( a : 3 + 15 ) = 72

a : 3 + 15 = 90 - 72

a : 3 + 15 = 18

a : 3 = 18 - 15

a : 3 = 3

a = 3 × 3

a = 9