Question

17. efectuați

a. 12/17 ×[(1 - 1/4) × 1/5 + (1- 1/5) × 1/6]

b. [( 5/9 - 17/4 : 51/2 ) × 3/8 + 1/6 ] : 15/16

c. 15/13× [9/10 - 1/13 × (25/12 - 17/20 - 12/15)


/= linia de fracție
× - înmulțit nu X

va rog repede e ptr maine la temaaaaa!!! ​

Answer 1

Răspuns:

a. 12/17 ×[(1 - 1/4) × 1/5 + (1- 1/5) × 1/6]

=12/17×(4-1)/4×1/5+(5-1)/5×1/6

=12/17×3/4×1/5+4/5×1/6

=3/17×3/1×1/5+2/5×1/3

=9/17×1/5+2/15

=9/85+2/15

=(9××3+2×17)/85×3

=(27+34)/255

=61/255

b. [( 5/9 - 17/4 : 51/2 ) × 3/8 + 1/6 ] : 15/16

=[(5/9-17/4×2/51)×3/8+1/6]×16/15

=[(5/9-1/2×1/3)×3/8+1/6]×16/15

=[(5/9-1/6)×3/8+1/6]×16/15

=[(5×2-1×3)/18+1/6]×16/15

=(7/18+1/6)×16/15

=(7+3)/18×16/15

=10/18×16/15

=2/18×16/1

=1/9×16/1

=16/9

c. 15/13× [9/10 - 1/13 × (25/12 - 17/20 - 12/15)

=15/13×[9/10-1/13×(25×5-17×3-12×4)/60]

=15/13×[9/10-1/13×(125-51-48)/60]

=15/13×[9/10-1/13×26/60]

=15/13×(9/10-2/60)

=15/13×(9/10-1/30)

=15/13×(9×3-1)/30

=15/13×26/30

=15/1×2/30

=1/1×2/2

=2/2

=1