- Rational Numbers
- Linear Equations in One Variable
- Understanding Quadrilaterals
- Practical Geometry
- Data Handling
- Squares and Square Roots
- Cubes and Cube Roots
- Comparing Quantities
- Algebraic Expressions and Identities
- Visualising Solid Shapes
- Mensuration
- Exponents and Powers
- Direct and Inverse Proportions
- Factorisation
- Introduction to Graphs
- Playing with Numbers
NCERT Solutions Class 8 Mathematics Solutions for Exercise 9.3 in Chapter 9 - Algebraic Expressions and Identities
Prev
Q5) Add: p\left(p-q\right),\ q\left(q-r\right)\ and\ r\left(r-p\right)
(b) Add: 2x\left(z-x-y\right)and\ 2y\left(z-y-zx\right)
(c) Subtract: 3l\left(l-4m+5n\right)from\ 4l\left(10n-3m+2l\right)
(d) Subtract: 3a\left(a+b+c\right)-2b\left(a-b+c\right)from\ 4c\left(-a+b+c\right)
Solution:
(a) p\left(p-q\right)+q\left(q-r\right)+r\left(r-p\right)
= p^2-pq+q^2-qr+r^2-rp
= p^2+q^2+r^2-pq-qr-rp
(b) 2x(z-x-y)+2y(z-y-z)
= 2xz-2x^2-2xy+2yz-2y^2-2xy
= 2xz-2xy-2xy+2yz-2x^2-2y^2
= -2x^2-2y^2-4xy+2yz+2zx
(c) 4l\left(10n-3m+2l\right)-3l\left(l-4m+5n\right)
= 40\ln-12lm+8l^2-3l^2+12lm-15l\ n
= 8l^2-3l^2-12lm+12lm+40\ln-15\ln
= 5l^2+25\ln
(d) 4c\left(-a+b+c\right)\ -\left[3a\left(a+b+c\right)-2b\left(a-b+c\right)\right]
= -4ac+4bc+4c^2-\left[3a^2+3ab+3ac-2ab+2b^2-2bc\right]
= -4ac+4bc+4c^2-\left[3a^2+2b^2+3ab-2bc+3ac-2ab\right]
= -4ac+4bc+4c^2-\left[3a^2+2b^2+ab+3ac-2bc\right]
= -4ac+4bc+4c^2-3a^2-2b^2-ab-3ac+2bc
= -3a^2-2b^2+4c^2-ab+4bc+2bc-4ac-3ac
= -3a^2-2b^2+4c^2-ab+6bc-7ac
Facebook
Whatsapp
Copy Link
Lido
Courses
Quick Links
Terms & Policies
Terms & Policies
