Question

If (a-b)=11 a^2+b^2=122 find ab
what is this answer​

Answer 1

• a-b=11
• a^2+b^2=122

We know

$\boxed{\sf (a-b)^2=a^2-2ab+b^2}$

$\\ \sf\longmapsto a-b=11$

$\\ \sf\longmapsto (a-b)^2=11^2$

$\\ \sf\longmapsto a^b+b^2-2ab=121$

$\\ \sf\longmapsto 122-2ab=121$

$\\ \sf\longmapsto 122-121=2ab$

$\\ \sf\longmapsto 2ab=1$

$\\ \sf\longmapsto ab=\dfrac{1}{2}$