Question

ex 5 si ex 6 mates19 help meee

Answer 1

5. fie x pretul initial
x-10/100×x=40.5
x(1-10/100)=40.5
x(100/100-10/100)=40.5
x×90/100=40.5
x=40.5 × 100/90
x=40.5×10/9
x=405/9
x=45

deci raspunsul e d

6. x/y=3/5 deci x=3y/5
x+y=40
inlocuim
3y/5+y=40
3y/5+5y/5=40
8y/5=40
8y=200
y=25
deci x=40-25=15

3x+y=3×15+25
=45+25
=70

deci raspunsul e c