Prove or disprove: a+b=a+b\sqrt{a + b} = \sqrt{a} + \sqrt{b}a+b=a+b for all a,b≥0a, b \geq 0a,b≥0.
True for all a,b≥0a, b \geq 0a,b≥0
False; counterexample: a=9,b=16a = 9, b = 16a=9,b=16
True only when a=ba = ba=b
False; but true when either a=0a = 0a=0 or b=0b = 0b=0