Question

suma a doua nemere este 5 3supra4 iar differenta lor este 5 supra4 aflati numerele




dau coroana si 20 p

Answer 1

a+b=5 *3/4 =>a+b= 23/4 (introducem intregii in fractie)
a-b=5/4
Observam ca se obtine un sistem de doua ecuatii cu doua necunocute.
Folosim metoda reducerii:$\left \{ {{a+b= \frac{23}{4} } \atop {a-b= \frac{5}{4} }} \right.$
Se reduce b cu -b si obtinem : 2a=28/4 |:2 =>a=7/2
Il aflam si pe b: 7/2 +b=23/4 =>b=23/4 -14/4 (l-am amplificat pe 7/2 cu 2) =>b=9/4
a=7/2
b=9/4

Answer 2

a+b=5 3/4 =5•4+3/4=23/4; a-b=5/4; => a=b+5/4 ; inlocuim: b+5/4+b=23/4; 2b+5/4=23/4; 2b=23/4-5/4; 2b=23-5/4=18/4; b=18/4 : 4/2=18/4 • 2/4=9/2•1/2=9/4; a=9/4+5/4=14/4; verificare: 9/4+14/4=23/4; 14/4-9/4=5/4