-5x^2+2x+16=(x-2)^2    7-5(x+6)=-3(8-x)    2x-3=0.5(x-1)+2    

1) -5x^2+2x+16=x^2-4x+4     -5x^2+2x+16-x^2+4x-4=0     -6x^2+6x+12=0 |:(-6)      x^2-x-2-0      D=1-4*1*(-2)=1+8=9      x1=1-3/2=-2/2=-1      x2=1+3/2=4/2=2   2) 7-5x-30=-24+3x     7-5x-30+24-3x=0     -8x=-1     x=1/8   3) 2x-3=0,5x-0,5+2     2x-0,5x=2-0,5+3     1,5x=4,5     x=3

-5x^2+2x+16=(x-2)^2  -5x^2+2x+16 =x^2-4x+4 -6x2 + 6x + 12 = 0 Делим на 6: -x2 + x + 2 = 0 D = b2 - 4ac D = 1 + 8 = 9 = 3^2 x1,2 = -b ± √D/2a x1 = -1 + 3/-2 = - 2/2= -1 x2 = -1 - 3/-2= 4/2 = 2 Ответ: x1 = -1; x2 = 2 7-5(x+6)=-3(8-x) 7-5x-30=-24+3x -5x-3x=-24-7+30 -8x=-31+30 -8x=-1 x=0.125  2x-3=0.5(x-1)+2 2x-3=0.5x-0.5+2 2x-0.5x=2+3-0.5 1.5x=4.5 x=3