Question

un exercițiu a+b+c=7si 4×a+3×b+2×c=18 calculează (5×a+4×b+3×c)×(3×a+2×b+c)

Answer 1

este foarte simplu

daca a +b +c =7

si. 4a+3b+2c=18

5a+4b+3c = (a+b+c)+(4a+3b+2c)

5a+4b+3c=7+18=25

3a+2b+c= (4a+3b+2c )-(a+b+c)

3a+2b+c=18-7=11

(5a+4b+3c)×(3a+2b+c) = 25×11 =275

Answer 2

a+b+c=7

4×a+3×b+2×c=18

=>(5×a+4×b+3×c)×(3×a+2×b+c)

=(5×a+4b+3×c)=4×a+3×b+2×c+a+b+c

=7+18=25

(3×a+2×b+c)=4×a+3×b+2×c-a+b+c

=18-7=11

=>(5×a+4×b+3×c)×(3×a+2×b+c)

=25×11=275