a=x
b=x+7
c=13
c^2=a^2+b^2 PifagoR
169=x^2+x^2+14x+49
120=2x^2+14x
60=x^2+7x
x^2+7x-60=0
D=49+240=289
D=17^2
x1=-7+17/2=5
x2=-12 etot ne podxodit
a=5
b=12
P eto perimetr rewaetsya tak po moemu
P=a+b+c=5+12+13=30 sm
a=x
b=x+7
c=13
c^2=a^2+b^2 PifagoR
169=x^2+x^2+14x+49
120=2x^2+14x
60=x^2+7x
x^2+7x-60=0
D=49+240=289
D=17^2
x1=-7+17/2=5
x2=-12 etot ne podxodit
a=5
b=12
c=13
P eto perimetr rewaetsya tak po moemu
P=a+b+c=5+12+13=30 sm