Respuesta :

  • 9x²+24x+20=4
  • (3x)²+2(3x)(4)+20-4=4-4
  • (3x)²+2(3x)(4)+16=0
  • (3x)²+2(3x)(4)+4²=0
  • (3x+4)²=0
  • 3x+4=0
  • x=-4/3

Answer:

[tex]\huge\boxed{\bf\:x = -\frac{4}{3}}[/tex]

Step-by-step explanation:

[tex]9x ^ { 2 } +24x+20=4[/tex]

Bring 4 to the left hand side of the equation .

[tex]9x^{2}+24x+20-4=0[/tex]

Subtract 4 from 20.

[tex]9x^{2}+24x+16=0[/tex]

Now, factorise it using the splitting-the-middle-term method .

[tex]9x^{2}+24x+16=0 \\9x^{2}+12x+12x+16 =0\\\left(9x^{2}+12x\right)+\left(12x+16\right)=0 \\3x\left(3x+4\right)+4\left(3x+4\right) =0\\\left(3x+4\right)\left(3x+4\right) = 0\\\left(3x+4\right)^{2} = 0[/tex]

Now since both the factors are the same, take one of them,

[tex]3x + 4 = 0\\3x = - 4\\\boxed{\bf\:x = -\frac{4}{3}}[/tex]

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