2x^2+7x-9=0
3x^2=18x
100x^2-16=0
x^2-16x+63=0

1)  2x^2+7x-9=0x1= (-7-√(49+72))/4 = -18/4= - 9/2x2= (-7+√(49+72))/4 = 12)  3x^2=18x3x(x-6)=0  x1=0  x2=63)  100x^2-16=04(5x-2)(5x+2)=0x1=2/5   x2=-2/54)  x^2-16x+63=0x1=(16-√(16²-4·63))/2=(16-2)/2=7   x2=(16+√(16²-4·63))/2=(16+2)/2=9