Question

9 Class math formula of all chapters

Answer 1

(a+b)2=a2+2ab+b2
(a−b)2=a2−2ab+b2
(a+b)(a–b)=a2–b2
(x+a)(x+b)=x2+(a+b)x+ab(x+a)(x–b)=x2+(a–b)x–ab(x–a)(x+b)=x2+(b–a)x–ab(x–a)(x–b)=x2–(a+b)x+ab(a+b)3=a3+b3+3ab(a+b)(a–b)3=a3–b3–3ab(a–b)(x+y+z)2=x2+y2+z2+2xy+2yz+2xz(x+y–z)2=x2+y2+z2+2xy–2yz–2xz(x–y+z)2=x2+y2+z2–2xy–2yz+2xz(x–y–z)2=x2+y2+z2–2xy+2yz–2xzx3+y3+z3–3xyz=(x+y+z)(x2+y2+z2–xy–yz−xzx2+y2=12[(x+y)2+(x–y)2](x+a)(x+b)(x+c)=x3+(a+b+c)x2+(ab+bc+ca)x+abcx3+y3=(x+y)(x2–xy+y2)x3–y3=(x–y)(x2+xy+y2)x2+y2+z2−xy–yz–zx=12[(x−y)2+(y−z)2+(z−x)2]

Answer 2

(a+b)²=a²+2ab+b²
(a-b)²=a²-2ab+b²
a²-b²=(a+b)(a-b)
(a+b)³=a³+b³+3ab(a+b)
(a-b)³=a³+b³-3ab(a-b)
(a+b+c)²=a²+b²+c²+2ab+2bc+2ca
a³+b³+c³-3abc=(a+b+c)(a²+b²+c²-ab-bc-ca)
area of triangle=√s(s-a)(s-b)(s-c)
area of parallelogram= b*h
area of rhombus=1/2*d1*d2