Question

calculati numerele a si b stiind ca a/5 =b/7 si a+5/b+1=a+b/b+10. Va rog e urgent!!!​

Answer 1

Răspuns:

Explicație pas cu pas:

a/5 = b/7

(a + 5)(b + 10) = (b + 1)(a + b)

ab + 10a + 5b  + 50 = ab + b^2 + a + b

b^2 - 9a - 4b - 50 = 0

a = 5b/7

b^2 - 45b/7 - 4b - 50 = 0

b^2 - 45b/7 - 28b/7 - 50 = 0

b^2 - 73b/7 - 50 = 0

7b^2 - 73b - 350 = 0

= 5329 + 9800 = 15129 = 123^2

b1 = (73 + 123)/14 = 14

a1 = 5*14/7 = 10

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b2 = (73 - 123)/14 = -50/14 = -25/7

a2 = -5*25/7*7 = -125/49