Question

Janelle was trying to find the distance between (3,7) and (9,6) in the coordinate plane. She knew the formula was D=√(9 - 3)^2 + (6 - 7)^2. So she took the square root and got (9-3)+(6-7)=5. Did she get the correct answer? Explain.

Answer 1

hello : 
incorrect  answer because : 
$\sqrt{ a^{2} + b^{2} } \neq \sqrt{ a^{2} } + \sqrt{ b^{2}} \neq a+b$
but : 
$\sqrt{ (a+b)^{2} } = a+b$........a+b ≥ 0