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Question Number 75932 by Rio Michael last updated on 21/Dec/19

solve for x the following  a. ∣x∣ + 3x −4 =0  b.  ∣x∣−1 = 0  c. x^2 +3∣x∣ +2 =0

solveforxthefollowinga.x+3x4=0b.x1=0c.x2+3x+2=0

Commented by mathmax by abdo last updated on 21/Dec/19

c)  x^2  +3∣x∣+2 =0 ⇔ ∣x∣^2 +3∣x∣+2=0 ⇒t^2  +3t +2=0 whit t=∣x∣  so t must be ≥0  Δ=3^2 −4.2 =1 ⇒t_1 =((−3+1)/2) =−1  t_2 =((−3−1)/2) =−2  all values of t are <0 ⇒ no solutions..

c)x2+3x+2=0x2+3x+2=0t2+3t+2=0whitt=∣xsotmustbe0Δ=324.2=1t1=3+12=1t2=312=2allvaluesoftare<0nosolutions..

Answered by benjo last updated on 21/Dec/19

Commented by Rio Michael last updated on 21/Dec/19

why sir

whysir

Commented by mr W last updated on 22/Dec/19

x^2 ≥0  ∣x∣≥0  x^2 +3∣x∣+2≥2  therefore x^2 +3∣x∣+2=0 is impossible.  i.e. x^2 +3∣x∣+2=0 has no (real)  solution.

x20x∣⩾0x2+3x+22thereforex2+3x+2=0isimpossible.i.e.x2+3x+2=0hasno(real)solution.

Commented by benjo last updated on 24/Dec/19

how about in complex solution sir?

howaboutincomplexsolutionsir?

Commented by mr W last updated on 24/Dec/19

complex solution:  let x=bi  −b^2 +3∣b∣+2=0  ∣b∣^2 −3∣b∣−2=0  ∣b∣=((3+(√(17)))/2)  ⇒x=±((3+(√(17)))/2)i

complexsolution:letx=bib2+3b+2=0b23b2=0b∣=3+172x=±3+172i

Commented by benjo last updated on 24/Dec/19

thanks you sir

thanksyousir

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