Răspuns :
a) a+b=15 c=3 ac+bc
a3+b3
3(a+b)
3×15=45
b) a-b=27 c=30 ca-cb
30a-30b
30(a-b)
30×27=810
c) xy+xz=126 x=5 y-z
5y+5z=126
5(y-z)=126
5×(y-z)=126
y+z= 126:5
y-z= 25.2
esti sigur ca e scrisa bine?
d) xy-xz=652 ×=5 y-z
5y-5z=652
5(y-z) = 652
5×(y-z) =652
652:5=130.4
×-y=130.4
esti sigur ca e scrisa bine?
a3+b3
3(a+b)
3×15=45
b) a-b=27 c=30 ca-cb
30a-30b
30(a-b)
30×27=810
c) xy+xz=126 x=5 y-z
5y+5z=126
5(y-z)=126
5×(y-z)=126
y+z= 126:5
y-z= 25.2
esti sigur ca e scrisa bine?
d) xy-xz=652 ×=5 y-z
5y-5z=652
5(y-z) = 652
5×(y-z) =652
652:5=130.4
×-y=130.4
esti sigur ca e scrisa bine?