Question

5 Află numărul x din egalitățile de mai jos.
a. (8 x 5 + 6 x 9 + x) : 9 +312 = 323
b. 4 x [(4 x x - 72): 4+20] - 64 = 20
100 - [250 - 5 x (x - 5): 5] x 3 = 40
d) 643 - [(x - 162): 5 + 159] = 454
e [(3 x x + 4) x 2 + 5] x 3 + 5 = 170
DAU COROANA LA CEL
BUN

rapid sunt in test!!!​

Answer 1

Răspuns:

a. (8×5+6×9+×):9+312=323

(40+54+×):9=323-312

(94+×):9=11

94+×=11×9

94+×=99

×=99-94

×=5

b.4×[(4×X-72):4+20]-64=20

4×(4×X-72):4+20=20+64

4×(4×X-72):4+20=84

4×(4×X-72):4=84-20

4×(4×X-72):4=64

4×(4×X-72)=64×4

4×(4×X-72)=256

4×X-72=256:4

4×X-72=64

4×X=64+72

4×X=136

X=136:4

X=34

c.100-[250-5×(X-5):3]=40

250-5×(X-5):3=100-40

250-5×(X-5):3=60

250-5×(X-5)=60×3

250-5×(X-5)=180

5×(X-5)=250-180

5×(X-5)=70

X-5=70:5

X-5=14

X=14+5

X=19

d.643-[(X-162):5+159]=454

(X-162):5+159=643-454

(X-162):5+159=189

(X-162):5=189-159

(X-162):5=30

X-162=30×5

X-162=150

X=150+162

X=312

e.[(3×X+4)×2+5]×3+5=170

[(3×X+4)×2+5]×3=170-5

[(×X+4)×2+5]×3=165

(3×X+4)×2+5=165:3

(3×X+4)×2+5=55

(3×X+4)×2=55-5

(3×X+4)×2=50

3×X+4=50:2

3×X+4=25

3×X=25-4

3×X=21X

X=21:3

X=7