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DC2000
Lv 5
DC2000 asked in Science & MathematicsMathematics · 1 decade ago

Can someone check my work? (Algebra)?

Problem is 2[z/2 + 1] ² - 3[z/2 + 1] = -1 I am to solve for z

This is what I got:

= (2z – 1) [2(z-1)]+1

= (2z – 1) (2z – 2)

= (2z – 1) ²

3 Answers

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  • 1 decade ago
    Favorite Answer

    The easiest way to do this is to let x = z/2 + 1

    Now you have 2x^2 - 3x = -1. Then add 1 to both sides

    2x^2 - 3x + 1 = 0

    Then factor by FOIL: (2x-1)(x-1) = 0

    so either 2x-1 = 0 meaning x = 1/2, or x-1 = 0 meaning x=1

    Then put back z/2 + 1 for x:

    z/2 + 1 = 1/2 or z/2 + 1 = 1

    Solve these for z.

  • cidyah
    Lv 7
    1 decade ago

    To solve for z, you must find the value of z.

    2[z/2+1]^2=2[z^2/4+z+1]=z^2/2+2z+2 --- (1)

    -3[z/2+1]=-3z/2-3 -----(2)

    we have (1)+(2)=-1

    z^2/2+2z+2-3z/2-3+1=0

    z^2+4z-3z=0

    z^2+z=0

    z(z+1)=0

    z=0 or z=-1

  • 1 decade ago

    0=2[z/2+1]^2-3[z/2+1]+1

    let a=[z/2+1], then you'll have a quadratic equation: 0=2a^2 - 3a+1

    solving for a using the quadratic formula will yield a=1 or 1/2

    then, substituting it back and solving for z will give you z=0 or -1.

    =)

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