7. a (3a - 2) - 1
8. a b
9. 3-a (4 + 7a)
10. (2a + b)2 - 6a - 36 - 4
11. 1 - 2a - 2b - 3 (a + b)2
12. 3a2 - 1-2a
13 2 + 3x + 2 + ax + 2a
Answers
Answer:
ANSWER:
(i)
5x + 7x + (-6x)
= 5x + 7x -6x
= 6x
(ii)
3
5
x +
2
3
x +
-4
5
x=
9x +10x -12x
15
=
7x
15
(iii)
5a2b +( −8a2b) + 7a2b
= 5a2b − 8a2b + 7a2b
4a2b
(iv)
3
4
x2 + 5x2+ (-3x2 ) + (-
1
4
x2)=
3
4
x2 -
1
4
x2 + 5x2-3x2=
1
2
x2 + 2x2 =
5
2
x2
(v) Collecting like terms and adding them:
x − 3y + 4z + y − 2x − 8z + 5x − 2y − 3z
= x- 2x + 5x - 3y + y - 2y + 4z - 8z - 3z
= 4x -4y -7z
(vi) Collecting like terms and adding them:
2x2 − 3y2 + 5x2 + 6y2 + (− 3x2 − 4y2)
= 2x2 + 5x2 - 3x2 - 3y2 +6y2 -4y2= 4x2 -y2
(vii) Collecting like terms and adding them:
5x − 2x2 − 8 + 8x2 − 7x − 9 + 3 + 7x2 − 2x
= -2x2 +8x2 + 7x2 + 5x - 7x - 2x -8 -9 + 3= 13x2 -4x -14
(viii) Collecting like terms and adding them:
2
3
a-
4
5
b+
3
5
c +(-
3
4
a -
5
2
b+
2
3
c )+
5
2
a+
7
4
b-
5
6
c b -
5
2
b +
7
4
b +
3
5
c +
2
3
c -
5
6
c =
(8 -9 +30)a
12
+
(-16 - 50 +35)b
20
+
(18 +20 -25)c
30
=
29
12
a -
31
20
b +
13
30
c
(ix) Collecting like terms and adding them:
8
5
x+
11
7
y+
9
4
xy + (-
3
2
x-
5
3
y-
9
5
xy)=
8
5
x -
3
2
x+
11
7
y -
5
3
y +
9
4
xy -
9
5
xy =
1
10
x -
2
21
y +
9
20
xy