Respuesta :
Answer:
x = -7 ±√5 /2
That is;
x = StartFraction negative 7 plus-or-minus StartRoot 5 EndRoot Over 2 EndFraction
Step-by-step explanation:
To find the solutions to the equation, we will follow the steps below
(2x + 3)² + 8(2x + 3) + 11 = 0 --------------------------------------------------------------(1)
let u = 2x + 3
we will replace 2x+ 3 by u in equation (1)
u² + 8u + 11 = 0 -----------------------------------------------------------------------------(2)
we will solve equation (2) using the formula method
a=1 b=8 and c=11
u = -b ± √b² - 4ac /2a
u = -8 ±√(-8)² - 4(1)(11) /2(1)
u = -8 ±√64 - 44 /2
u = -8 ±√20 /2
u = -8/2 ± √20/2
u= -4 ± √20/2
u= -4 ± √5×4 /2
u= -4 ± 2√5 /2
u= -4 ± √5 ---------------------------------------------------------------------------(30
but u = 2x + 3
Substitute u =2x+3 in equation (3)
2x + 3 = -4 ± √5
subtract 3 from both-side of the equation
2x + 3-3 = -4 -3 ± √5
2x = -7±√5
Divide both-side of the equation by 2
2x/2 = -7 ±√5 /2
x = -7 ±√5 /2
