Question

find thr roots by completing the square method i) x^2-4x-21=0 ii) x^2-25+156=0 iii) x^2 -8x-180 iv) x^2 -80x -2700

Answer 1

☜☆☞hey friend ☜☆☞

here is your answer ☞
_______

(1)
=> x²-4x-21=0
=> x²-7x+3x-21=0
=> x(x-7) +3(x-7)
=> (x-7)(x+3)
=> {x=7, or x=-3}_______answer

(2)
=> x²-25x+156=0
=> x²-12x-13x+156=0
=> x(x-12)-13(x-12)=0
=> (x-12)(x-13) = 0
=> {x=12 or x=13}_____answer

(3)
=> x²-8x-180=0
=> x²-18x+10x-180=0
=> x(x-18)+10(x-18)=0
=> (x+10)(x-18)=0
=> {x=-10 or x=18}_____answer

(4)
=> x²-80x-2700=0
=> {x=105.57 or x= -25.57}____answer

hope it will help you

Devil_King ▄︻̷̿┻̿═━一