问题1.确定下列各表达式的项及其系数。
Need to be Known:
- Expression: An Expression is the addition of terms. Example: 7y + z is an expression made up of two terms 7y and z.
- Term: Terms itself is a product of factors. Example: 7y + z, here terms are 7y (term 1) and z (term2) where term 1 is the product of two factors 7 and y . and term 2 is a single factor z.
- Coefficient: It is a numerical factor of the term. Example: 7y + z here term1 has a two factor 7 and y in which 7 is numerical factor hence it is a coefficient.
(i)5xyz 2 – 3zy
解决方案:
- Here terms are 5xyz2 and -3zy
- Here Coefficients are 5 and -3
(ii)1 + x + x 2
解决方案:
- Here terms are 1, x, x2
- Here Coefficients are 1, 1, 1
(iii)4x 2 y 2 – 4x 2 y 2 z 2 + z 2
解决方案:
- Here terms are 4x2y2, –4x2y2z2 and z2
- Here Coefficients are 4, -4 and 1
(iv) 3 – pq + qr – rp
解决方案:
- Here terms are -3, -pq, qr, -rp
- Here Coefficients are 3, -1, 1 and -1
(v) x / 2 + y / 2-xy
解决方案:
- Here terms are x/2, y/2 and -xy
- Here Coefficients are 1/2, 1/2 and -1
(vi)0.3a – 0.6ab + 0.5b
解决方案:
- Here terms are 0.3a, -0.6ab and 0.5b
- Here Coefficients are 0.3, -0.6 and 0.5
问题2.将以下多项式分类为单项式,二项式和三项式。哪些多项式不适合这三个类别中的任何一个?
X + Y,1000,X + X 2 + X 3 + X 4,7 + Y + 5倍,2Y – 3Y 2,2Y – 3Y 2 + 4Y 3,5× – 4Y + 3XY,4Z – 15Z 2,AB + BC + CD + DA,PQR,p 2 q + PQ 2,2P + 2Q
Need to be Known:
- Monomial: Expression made up of one term is known as monomial. Example: pqr, z, ab etc.
- Binomial: Expression made up of two terms is known as binomial. Example: 2y + 3z, 5x – 4y, etc.
- Trinomial: Expression made up of three terms is known as trinomial. Example: 2y + 3z + x, 5x – 4y + a, etc.
- Polynomial: Expression made up of one or more terms is known as a polynomial. Example: a + b + c + d, 3xy, 7xyz – 10, 2x + 3y + 7z, etc
解决方案:
In this question:
- Monomials: 1000, pqr
- Binomials: x + y, 2y – 3y2, 4z – 15z2, p2q + pq2, 2p + 2q
- Trinomials: 7 + y + 5x, 2y – 3y2+ 4y3, 5x – 4y + 3xy
- and those which do not fit in these categories are: x + x2+ x3+ x4, ab + bc + cd + da
问题3.添加以下内容
Need to be Known:
Like term: Terms having the same variable with their same power.
Note**: Terms those are like can only add and subtract each other. unlike terms cannot add and subtract each other. Example: 4x and 5x are like terms as they both have the same coefficient with the same power of x as 1.
Unlike term: Terms having different variable and may have different powers.
- Example: 4x and 5y are unlike terms as they both have different variables
- Example: 4x2 and 5x3 are unlike terms as they both terms differ in the variable power.
(i)ab – bc,bc – ca,ca – ab
解决方案:
As here three expressions are given, we need to place expressions same terms below other expressions same term one by one then we will get like these:
ab – bc + 0
+ 0 + bc – ca
+ -ab + 0 + ca
_________________
0 + 0 + 0 <———-final expression
_________________
this tends to 0.
(ii)a – b + ab,b – c + bc,c – a + ac
解决方案:
As here three expressions are given, we need to place expressions same terms below other expressions same term one by one then we will get like these:
a – b + ab
+ 0 + b + 0 – c + bc
+ -a + 0 + 0 + c + 0 + ac
__________________________
0 + 0 + ab + 0 + bc + ac <—- final expression
_____________________________
this tends to ab + bc + ac.
(iii)2p 2 q 2 – 3pq + 4,5 + 7pq – 3p 2 q 2
解决方案:
As here two expressions are given, we need to place expressions same terms below other expressions same term one by one then we will get like these:
2p2q2 – 3pq + 4
+ -3p2q2 + 7pq +5
__________________
-1p2q2 + 4pq + 9 <——– final expression
____________________
this tends to -1p2q2 + 4pq + 9.
(ⅳ)升2 + M 2,M 2 + N 2,N 2 + L 2,2LM + 200万+ 2NL
解决方案:
As here four expressions are given, we need to place expressions same terms below other expressions same term one by one then we will get like these:
l2 + m2
+ 0 + m2 + n2
+ l2 + 0 + n2
+ 0 + 0 + 0 + 2lm + 2mn + 2nl
_________________________________
2l2 + 2m2 + 2n2 + 2lm + 2mn + 2nl <———final expression
___________________________________
as 2 is common among all terms then we can take it common this tends to 2( l2 + m2 + n2 + lm + mn + nl)
问题4。
(a)从12a – 9ab + 5b – 3中减去4a – 7ab + 3b + 12
解决方案:
Here we need to substract the given expressions:
then,
12a – 9ab + 5b – 3
(-) 4a – 7ab + 3b + 12
________________________
in substraction sign of (-) expression gets altered as:
12a – 9ab + 5b – 3
– 4a + 7ab – 3b – 12
________________________
8a – 2ab + 2b – 15 <———final expression
__________________________
this tends to 8a – 2ab + 2b – 15 .
(b)从5xy – 2yz – 2zx + 10xyz减去3xy + 5yz – 7zx
解决方案:
Here we need to subtract the given expressions:
then,
5xy – 2yz – 2zx + 10xyz
(-) 3xy + 5yz – 7zx + 0
___________________________
in substraction sign of (-) expression gets altered as:
5xy – 2yz – 2zx + 10xyz
-3xy – 5yz + 7zx – 0
___________________________
2xy – 7yz + 5zx + 10xyz <———– final expression
_____________________________
this tends to 2xy – 7yz + 5zx + 10xyz.
(c)从18 – 3p – 11q + 5pq – 2pq 2 + 5p 2 q减去4p 2 q – 3pq + 5pq 2 – 8p + 7q – 10
解决方案:
Here we need to substract the given expressions:
then, 5p2q + 5pq – 2pq2 – 3p – 11q + 18
(-) 4p2q – 3pq + 5pq2 – 8p + 7q – 10
__________________________________
in substraction sign of (-) expression gets altered as:
5p2q + 5pq – 2pq2 – 3p – 11q + 18
-4p2q + 3pq – 5pq2 + 8p – 7q + 10
__________________________________
p2q + 8pq – 7pq2 + 5p – 18q + 28 <———–final expression
_____________________________________
this tends to p2q + 8pq – 7pq2 + 5p – 18q + 28