Question

What are the solutions of the equation (2x + 3)^2 + 8(2x + 3) + 11 = 0? Use u substitution and the quadratic formula to solve.

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Answer 1

u=2x+3, x=u/2-3/2
u^2+8u+11=0
u1=(-8+sqrt(64-44))/2=-4+sqrt(5)
u2=-4-sqrt(5)
x1=u1/2-3/2=-7/2+sqrt(5)/2
x2=u2-3/2=-7/2-sqrt(5)/2