Question

x elevado a 2-9x+20=0

Answer 1

$x {}^{2} - 9x + 20 = 0 \\ x {}^{2} - 4x - 5x + 20 = 0 \\ x \times (x - 4) - 5(x - 4) = 0 \\ (x - 4) \times (x - 5) = 0 \\ x - 4 = 0 \\ x - 5 = 0 \\ x {}^{1} = 4 \\ x {}^{2} = 5$