Akar akar persamaan log (x² + 7x + 20)=1 adalah x1 dan x2. hitunglah (x1+x2)²- 4x1x2 mohon bantuanya

log (x² + 7x + 20) = 1
log (x² + 7x + 20) = log 10
x² + 7x + 20 = 10
x² + 7x + 20 - 10 = 0
x² + 7x + 10 = 0

x1 + x2 = -b/a = -7
x1 . x2 = c/a = 10

(x1 + x2)² - 4x1.x2
(-7)² - 4(10) = 49 - 40 = 9