Question

12 pontos por fvorzin e pra amanhã cedo

Answer 1

vou responder a 6 e a 7
6-)x + x² = 90
x + x² -90 = 0
Δ=b² - 4 .a.c
Δ=1² - 4 .1 . -90
Δ=1  + 360
Δ =361
\/¨¨¨361 =19
x = -b +ou-19/2.1
x´= -1+19/2
x´= 18/2 ⇒9
x" =- 1-19/2
x" = -20/2 ⇒-10
S = {-10,9 }

7-)x² + x = 12
x² + x - 12 = 0
Δ = b² - 4 . a . c
Δ = 1² - 4 . 1. -12
Δ = 1  + 48
Δ = 49
\/¨¨49 = 7
x = - b +ou- 7/2.1
x´= -1 +ou-7/2
x´= -1+7/2
x´= 6/2 ⇒3
x" = -1 - 7 /2
x" = -8 /2 ⇒-4
S = {-4 , 3 }