Answers
1) In a polynomial the exponents of the variable is always
b) Positive
2) Which of the following is correct ?
a) (a – b)² = a² – 2ab + b²
3) The sum of –7pq and 2pq is
–7pq + 2pq = –5pq
d) –5pq
4) If we subtract –3x²y² from x²y², then we get
–3x²y² from x²y²
x²y² – (–3x²y2)
x²y²+3x²y²
4x²y²
d) 4x²y²
5) Area of rectangle with length 4ab and breadth 6b² is
a) 24a²b²
6) Volume of a rectangular box with Length = 2ab, Breadth = 3ac and height = 2ac.
Volume of cuboid = Length × Breadth × Height
Volume = 2ab × 3ac × 2ac
So Volume = 12a³bc²
a) 12a³bc²
7) Common factor of 17abc, 34ab²,51a² is
To get the common factor we need to factorise 17abc, 34ab²and 51a²
17abc, 34ab², 51a²b
17ab(c, 2b, 3a)
b) 17ab
8) Factorised form r² – 10r + 21
r² –(7+3)r + 21
r² – 7r – 3r + 21 __________ [By middle term factorisation]
r(r–7) – 3(r–7)
(r–7)(r–3)
b) (r–7)(r–3)
II)1) Answer the following :
i) (x+3)(x+7)
x²+ (7+3)x + 7×3 Using identity (x+a)(x+b)
x²+10x+21
ii) (xy + yz)²
(xy)² + 2•xy•yz + (yz)² Using identity (a+b)²
x²y² + 2xy²z + y²z²
2) Using suitable identity, evaluate :
I) (52)²
(50+2)² Using identity (a+b)²
(50)² + 2•50•2 + (2)²
2500 + 200 + 4
2700 + 4
2704
II) (103)²
(100+3)²
(100)² + 2•100•3 + (3)²
10000 + 600 + 9
10600 + 9
10609
III) 47 × 53
(50–3)(50+3) Using identity (a–b)(a+b)
(50)²–(3)²
2500–9
2491
IV) 9.8 × 10.2
(10–0.2)(10+0.2) Using identity (a–b)(a+b)
(10)² – (0.2)²
100–0.04
100.04
3) Factorise :
I) 6ab + 12 bc
6b(a+c)
II) –xy–ay
–y(x+a)
III) ax³ – bx² + cx
x(ax² – bx + c)
Step-by-step explanation:
Hey!
Given=mass of moon=7.36×10^22
mass of earth=6.37×10^24
radius of moon=1.74×10^6
g=GMm/Rm^2
g=6.67×10^-11*7.36×10^22/(1.74×10^6)^2
g=1.6ms-2
we can put the value of g=9.8ms-2
so,gm/ge=1.6/9.8=1/6
hope it helps you