Question

Stiind ca a=√81+√25 si b=√16+√49 sa se calculeze:
a) a+b b) a²-b² c) a²+b²-100

Answer 1

a=√81+√25 =9+5=14
b=√16+√49 =4+7=11

a) a+b =14+11=25
b) a²-b² =14²-11²=(14+11)(14-11)=25*3=75
c) a²+b²-100 =14²+11²-100=196+121-100=217

Answer 2

$a= \sqrt{81} + \sqrt{25} \\ a=9+5 \\ a=14 \\ b= \sqrt{16} + \sqrt{49} \\ b=4+7 \\ b=11 \\ a+b=14+11=25 \\ a^2-b^2=14^2-11^2=(14-11)(14+11)=196-121=75 \\ a^2+b^2-100=14^2+11^2-100=196+121-100=317-100=217$