Question

a) x-5/x-3
b)x²+9x=0

Answer 1

a) x - 5 = 1 / x - 3
(x - 5) (x - 3) = 1
x² - 5x - 3x + 15 = 1
x² - 8x + 15 - 1 = 0
x² - 8x + 14 = 0
a = 1
b = - 8
c = 14
Δ = b² - 4.a.c
Δ = (-8)² - 4.1 . 14
Δ = 64 - 56
Δ = 8
x = - b + - √Δ/2a
x = - (- 8 ) + - √8 / 2 . 1
x = 8 + - 2√2 / 2
x' = 4 + √2
x" = 4 - √2

S = { 4 + √2 e 4 - √2}

b) x² + 9x = 0
x( x + 9) = 0
x = 0
x + 9 =0
x = - 9

x' = 0
x" = - 9

S = { 0 e - 9 }