Question

Calculati:
(8x9+s-5x8)-(30-5x2+5)=100:2:2
(36-5x6-t)+9x8-7x10=4x7:7
(7x7-6x6+u)-24:3-2x10=81:9​

Answer 1

(8x9+s-5x8)-(30-5x2+5)=100:2:2

(72+s-40)-(30-10+5)=50:2

(72+s-40)-(20+5)=25

(72+s-40)-25=25

72+s-40=25+25

72+s-40=50

72+s=50+40

72+s=90

s=90-72

s=18

(36-5x6-t)+9x8-7x10=4x7:7

(36-30-t)+72-70=28:7

(6-t)+72-70=4

(6-t)+72=4+70

(6-t)+72=74

6-t=74-72

6-t=2

t=6-2

t=4

(7x7-6x6+u)-24:3-2x10=81:9

(49-36+u)-8-20=9

(13+u)-8=9+20

(13+u)-8=29

13+u=29+8

13+u=37

u=37-13

u=24