А
x²-2x+1+x²+4x+4-x²+4-24=0
x²+2x-15=0
(x²+2x+1)-16=0
(x+1)²-4²=0
(x+1-4)(x+1+4)=0
(x-3)(x+5)=0
x-3=0⇒x=3
x+5=0⇒x=-5
б
x²-4x+4+x²+2x+1-x²+1-14=0
x²-2x-8=0
(x²-2x+1)-9=0
(x-1)²-3²=0
(x-1-3)(x-1+3)=0
(x-4)(x+2)=0
x-4=0⇒x=4
x+2=0⇒x=-2
в
3(1-x²)=12*1-4(2x+1)
3-3x²=12-8x-4
3x²-8x+5=0
3(x²-8/3*x+5/3)=0
x²-8/3*x+5/3=0
(x²-2*4/3*x+16/9)-16/9+5/3=0
(x-4/3)²-(16+15)/9=0
(x-4/3)²-(1/3)²=0
(x-4/3-1/3)(x-4/3+1/3)=0
(x-5/3)(x-1)=0
x-5/3=0⇒x=5/3
x-1=0⇒x=1
г
5(x²-1)-15*2=3(2x-1)
5x²-5-30-6x+3=0
5x²-6x-32=0
5(x²-6/5*x-32/5)=0
x²-6/5*x-32/5=0
(x²-2*3/5*x+9/25)-9/25-32/5=0
(x-3/5)²-(9+160)/25=0
(x-3/5)²-(13/5)²=0
(x-3/5-13/5)(x-3/5+13/5)=0
(x-16/5)(x+2)=0
x-16/5=0⇒x=16/5=3,2
x+2=0⇒x=-2