Expand: (5y - 7)^2 =?

3 ⤊

2007-05-15 03:41:23 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

use (a-b)^2 = a^2+b^2-2ab
(5y-7)^2=25y^2+49-2(5y)(7)

= 25y^2-70y + 49

2007-05-15 03:50:11 · answer #1 · answered by TheWho 2 · 1⤊ 0⤋

25yÂ² - 70y + 49

2007-05-15 10:47:51 · answer #2 · answered by Robert L 7 · 1⤊ 0⤋

use the identity (a-b)^2=a^2-2ab+b^2

then you will get
25y^2-70y+49

2007-05-15 10:47:31 · answer #3 · answered by math 2 · 1⤊ 0⤋