What is an algebraic expression ?
An algebraic expression (or) a variable expression is a combination of terms by the operations such as addition, subtraction, multiplication, division.
For examples,
4x, 2a + 3b - 5, 3x2 - 4xy + 2y2
To simplify algebraic expressions, we need to know the like terms and unlike terms.
Like terms :
Like terms are the terms which have the same variables with same exponent for each variable.
7x, 3x, - 4x
Unlike terms :
Unlike terms are the terms which have same variables or different variables.
If they have same variables, the exponents will not be same.
9x2, 5xy, - 4xy2, y, 6
Problem 1 :
(4x + 7x)3
Solution :
= (4x + 7x)3
Distributing 3,
= [4x(3) + 7x(3)]
= 12x + 21x
= 33x
Problem 2 :
12z – 5z + 9z²
Solution :
= 12z – 5z + 9z²
= 7z + 9z²
Factoring z,
= 9z² + 7z
= z(9z + 7)
Problem 3 :
-7(-6m + 11m)
Solution :
= -7(-6m + 11m)
= -7(5m)
= -35m
Problem 4 :
4(11 – 3x)
Solution :
= 4(11 – 3x)
Distributing 4,
= 4(11) + 4(-3x)
= 44 – 12x
= -12x + 44
Problem 5 :
-5(5a – 3b - 6)
Solution :
= -5(5a – 3b - 6)
Distributing -5,
= -5(5a) -5(-3b) -5(-6)
= -25a + 15b +30
Problem 6 :
-2(x² - 8x + 3x³ - 6)
Solution :
= -2(x² - 8x + 3x³ - 6)
= -2(x²) - 2(-8x) - 2(3x³) - 2(-6)
= -2x² +16x – 6x³ + 12
= -6x³ - 2x² + 16x + 12
Problem 7 :
9x – 4(6 – 3x)
Solution :
= 9x – 4(6) -4(-3x)
= 9x – 24 + 12x
combining like terms,
= 21x - 24
Problem 8 :
5(3b – 2a) – 7b
Solution :
= 5(3b) + 5(-2a) – 7b
= 15b – 10a -7b
combining like terms,
= -10a +15b – 7b
= -10a + 8b
Problem 9 :
12 + 3(7x + 2)
Solution :
= 12 + 3(7x) + 3(2)
= 12 + 21x + 6
= 21x + 18
Problem 10 :
6(4y + 3z) – 11z
Solution :
= 6(4y) + 6(3z) – 11z
= 24y + 18z – 11z
= 24y – 7z
Problem 11 :
5 + 2(4m – 7n) + 9n
Solution :
= 5 + 2(4m) + 2(-7n) + 9n
= 5 + 8m – 14n + 9n
= 5 + 8m - 5n
Problem 12 :
12 – 7(3 – 5r) + 8r
Solution :
= 12 – 7(3) -7(-5r) + 8r
= 12 – 21 + 35r + 8r
= -9 + 43r
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