Question

daca a3 +b=7 si a+3b=9 caculati

Answer 1

3a+b=7
a+3b=9

3a+b=7
3a=7-b
a = $\frac{7-b}{3}$

a+3b=9
$\frac{7-b}{3}$ +3b=9
amplificam 3b cu 3 ==> $\frac{9b}{3}$=9
$\frac{7-b}{3}$  +  $\frac{9b}{3}$=9
$\frac{7-b +9b}{3}$=9
7+8b /3 =9
8b/3=2
8b=2 x 3
8b=6
b =$\frac{6}{8}$
3a+b=7
3a + 6/8 = 7
3a= 7 - 6/8
amplificam 7 cu 8
3a= $\frac{56}{8} - \frac{6}{8}$
3a =$\frac{50}{8}$
a = tex] \frac{50}{8} [/tex] : $\frac{3}{1}$
a= $\frac{50}{8}$ x $\frac{1}{3}$
a=$\frac{50}{24}$
a= 25/12 dupa simplificarea cu 2