1.a. x²-16x+28=0
x1+x2=-(-16)=16
x1×x2=28
x1=2
x2=14
1.b. x²-12x-45=0
x1+x2=-(-12)=12
x1×x2=-45
x1=-3
x2=15
2.a. x²-27x=0
x1+x2=-(-27)
x1×x2=0
x1=0
x2=27
2.b. y²-12=0
y1+y2=0
y1×y2=-12
y1=-√12
y2=√12
3.a. 3x²-6x-7=0|÷3
x²-(6/3)x-(7/3)=0
x²-2x-(7/3)=0
x1+x2=-(-2)=2
x1×x2=(-7/3)
3.b. 5y²+y-3=0|÷5
y²+(1/5)y-(3/5)=0
y²+0,2y-0,6=0
y1+y2=-0,2
y1×y2=-0,6