$a)(x+5)^2-(x-3)^2-32=0$
$⇔x^2+10x+25-x^2+6x-9-32=0$
$⇔16x=16$
$⇔x=1$
$b)(2x+1)^2+(x-4)^2-5(x+9)(x-9)=0$
$⇔4x^2+4x+1+x^2-8x+16-5(x^2-81)=0$
$⇔5x^2-4x+17-5x^2+405=0$
$⇔4x=422$
$⇔x=\dfrac{211}{2}$
$c)36x^2-49=0$
$⇔36x^2=49$
$⇔x^2=\dfrac{49}{36}$
$⇔$\(\left[ \begin{array}{l}x=\dfrac{7}{6}\\x=-\dfrac{7}{6}\end{array} \right.\)
$d)(x+7)^2-(x+5)(x-5)=-4$
$⇔x^2+14x+49-x^2+25=-4$
$⇔14x=-78$
$⇔x=-\dfrac{39}{7}$
