Question

y*(y+1)=135

Answer 1

y(y+1)=135

=> y²+y-135=0

=> y²+y+\(\frac{1}{4}\) - \(\frac{541}{4}\)=0

=> (y+\(\frac{1}{2}\))²-( \(\frac{\sqrt{541}}{2}\))²=0

=> (y+\(\frac{1}{2}\)-\(\frac{\sqrt{541}}{2}\))(y+\(\frac{1}{2}\)+\(\frac{\sqrt{541}}{2}\))=0

=> y =\(\frac{\sqrt{541}-1}{2}\), y =- \(\frac{\sqrt{541}+1}{2}\)

Answer 2

đây là cách giải lớp mấy vậy