Question

poate să îmi zică și mie cnv rsp la 13 și 14
urgent
mersi frumos​

Answer 1

13. a+b=15

a×b=36

a=15-b

(15-b)b=36

15b-b²=36

b²-15b+36=0

Δ=225-144=81

b=12     b=3

a=3       a=12

$\frac{3}{12}\times 100=25\%$

14.

$E(x)=(\frac{x-6}{(x-5)(x+5)} +\frac{x}{x-5} -\frac{2}{x+5} ):\frac{(2x-3)(x+2)}{(x-5)(x+5)} \\\\E(x)=\frac{x-6+x^2+5x-2x+10}{(x-5)(x+5)} \times \frac{(x-5)(x+5)}{(2x-3)(x+2)} \\\\E(x)=\frac{x^2+4x+4}{(2x-3)(x+2)} \\\\E(x)=\frac{(x+2)^2}{(2x-3)(x+2)}\\\\E(x)=\frac{x+2}{2x-3}$

(x+2)(2x-3)=2x²-3x+4x-6=2x²+x-6

E(a)∈Z

2a-3 | a+2   |× (-2)

2a-3 | 2a-3

2a-3 | -2a-4

2a-3 | 2a-3

2a-3 |-7

2a-3={-1,1,-7,7}

2a={2,4,-4,10}

a={1,2,-2,5}