Cho a^2+c^2=2b^2
Rút gọn:(a+b).(a+c)+(c+a).(c+b)=?
Giúp mik vs mai nộp rồi
Cho a^2+c^2=2b^2 Rút gọn:(a+b).(a+c)+(c+a).(c+b)=? Giúp mik vs mai nộp rồi
By Iris
By Iris
Cho a^2+c^2=2b^2
Rút gọn:(a+b).(a+c)+(c+a).(c+b)=?
Giúp mik vs mai nộp rồi
$(a+b)(a+c)+(c+a)(c+b)$
$=a^2+ac+ab+bc+c^2+bc+ac+ab$
$=(a^2+c^2)+(ac+ac)+(ab+ab)+(bc+bc)$
$=2b^2+2ac+2ab+2bc$
$=2b(a+b)+2c(a+b)$
$=(a+b)(2b+2c)$
` (a + b)(a + c) + (c + a)(c + b) `
` = a^2 + ac + ab + bc + c^2 + bc + ac + ab `
` = a^2 + c^2 + 2ac + 2bc + 2ab `
` = 2b^2 + 2ac + 2bc + 2ab `
` = 2a(b + c) + 2b(b + c) `
` = (2a + 2b)(b + c) `