Question

Calculează, scoțând factor comun pe grupe de
termeni:
a) 5.7 +5.13+15.8+15.12;
b) 7.21 +7.19-4.13-4.7;
c) 11 -23 +8.13-11-7-8.9;
d) 5.2 +5.7 +4.9-4-3-5-8.
va rog este urgent!!!​

Answer 1

a) 5x7 +5x13+15x8+15x12=

5(7+13)+15(8+12)=

5x20+15x20=

20(5+15)=

20x20=

=400

b) 7x21 +7x19-4x13-4x7=

7(21+19)-4(13+7)=

7x40-4x20=

280-80=

=200

c) 11 -23 +8x13-11-7-8x9=

-23+8x13-8x9-7=

-23+8(13-9)-7=

-23+8x4-7=

1-7=

=-6

d) 5x2 +5x7 +4x9-4-3-5-8=

5(2+7)+4x9-20=

5x9-4x9-20=

9(5-4)-20=

9-20=

=-11

Succes!