From the second equation, we have:
a(a+x)=b(b+y) a2+ax=b2+by ax−by=b2−a2 We are given ax+by=c2. Adding the two equations, we get:
ax−by+ax+by=b2−a2+c2 2ax=b2−a2+c2 x=2ab2−a2+c2 Subtracting the two equations, we get:
ax+by−(ax−by)=c2−(b2−a2) 2by=c2−b2+a2 y=2bc2−b2+a2 Now, we substitute x and y into the third equation x−y+z=5: 2ab2−a2+c2−2bc2−b2+a2+z=5 z=5−2ab2−a2+c2+2bc2−b2+a2 z=5+2bc2−b2+a2−2ab2−a2+c2 z=5+2aba(c2−b2+a2)−b(b2−a2+c2) z=5+2abac2−ab2+a3−b3+ba2−bc2 z=5+2abac2−bc2−ab2+a2b+a3−b3 z=5+2abc2(a−b)+ab(a−b)+(a−b)(a2+ab+b2) z=5+2ab(a−b)(c2+ab+a2+ab+b2) z=5+2ab(a−b)(c2+a2+2ab+b2) z=5+2ab(a−b)(c2+(a+b)2)