Question

-20=-X-X²
ME AJUDEM PRFVR ,, OBG

Answer 1

-20=-X-X² 
x² + x - 20 = 0
Δ = b² - 4*a*c
Δ = 1² - 4*1*(-20)
Δ = 1 + 80
Δ = 81

(-b+-√Δ)/2*a
(-1 +- √81)/2*1
(-1 +- 9)/2

x' = (-1 + 9)/2
x' = 8/2
x' = 4

x'' = (-1 - 9)/2
x'' = -10/2
x'' = -5

x' = 4
x'' = -5

Answer 2

-20=-X-X²

-20 = - x - x²    vamos igualar a ZERO
- 20 + x + x² = 0   ------(ARRUMAR  a casa)
x² + x - 20 = 0

ax² + bx + c = 0

x² + x - 20 = 0
a = 1
b = 1
c = - 20
Δ = b² - 4ac
Δ = (1)² - 4(1)(-20)
Δ = + 1 + 80
Δ = 81 ========> √Δ = 9   ======> √81 = 9
se
Δ > 0 (DUAS  raizes diferentes)
então
(baskara)

x = - b + √Δ/2a

x' = -1 + √81/2(1)
x' = - 1 + 9 /2
x' = + 8/2
x' = 4
e
x" = -1 - √81/2(1)
x" = -1 - 9/2
x" = - 10/2
x" = - 5

V = { -5; 4}
  
ME AJUDEM PRFVR ,, OBG