a=b+5
18=a*b/2=a*(a-5)/2=(a^2-5*a)/2
36=a^2-5*a
a^2-5*a-36=0
D=5^2-4*1*(-36)=25+144=169
X1=(5+13)/(2*1)=9
X2=(5-13)/(2*1)=-4
a=9
b=4
18=a*b/2=a*(a-5)/2=(a^2-5*a)/2
36=a^2-5*a
a^2-5*a-36=0
D=5^2-4*1*(-36)=25+144=169
X1=(5+13)/(2*1)=9
X2=(5-13)/(2*1)=-4
a=9
b=4