Question 618665
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Hi,
 1.4y^4+9=13y^2 (Let x = y^2) &#8658; 4x^2 -13x + 9 &#8658; (4x-9)(x-1) &#8658; x = 9/4, x = 1
   y^2 = 9/4, y = ±  3/2  OR y^2 = 1, y = ±  1
2.x-3x ^1/2+2=0 (s = x^2)&#8658; s^2-3s + 2 = 0 &#8658; (s-2)(s-1) = 0 &#8658; s = 2, s = 1
    x = ±  sqrt(s), x = ± sqrt(2), x = ± 1  
etc