Algebra Ex 3.17-10th Std Maths-Book Back Question And Answer
Question 1.
If then
verify that (i) A + B = B + A
(ii) A + (-A) = (-A) + A = O.
Answer:
From (1) and (2) we get A + B = B + A
From (1) and (2) we get
A + (-A) = (-A) + A = 0
Question 2.
If
then verify that
A + (B + C) = (A + B) + C.
Answer:
From (1) and (2) we get
A + (B + C) = (A + B) + C
Question 3.
Find X and Y if 
and
Answer:
Question 4.
If
find the value of (i) B – 5A (ii) 3A – 9B
Answer:
Question 5.
Find the values of x, y, z if
Answer:
(i) x – 3 = 1 ⇒ x = 1 + 3 ⇒ x = 4
3x – z = 0 (substitute the value of x)
3(4) – z = 0
12 – z = 0
∴ z = 12
x + y + z = 6
4 + y + 12 = 0
y + 16 = 6
y = 6- 16
∴ y = -10
The value of x = 4, y = -10 and z = 12
(ii) [x y – z z + 3] + [y 4 3] = [4 8 16]
x + y = 4 ….(1)
y – z + 4 = 8
Substitute the value
of z in (2)
(2) ⇒ y – 10 = 4
Substitute the value of y in (1)
z + 3 + 3 = 16
z + 6 = 16
z = 16 – 16 = 10
y = 14
(1) ⇒ x + 14 = 4
x – 4 – 14 = -10
The value of x = -10, y = 14 and z = 10
Question 6.
Find x and y if x
Answer:
4x – 2y = 4
(1) ⇒ 2x – y = 2
(2) ⇒ 3x – y = 2
– x + y = 2
Add (1) and (2)
Substitute the value of x = 4 in (2)
– 4 + y = 2
y = 2 + 4 = 6
The value of x = 4 and y = 6
Question 7.
Find the non-zero values of x satisfying the matrix equation
Answer:
The value of x = 4
Question 8.
Solve for x,y :
Answer:
x2 – 4x = -5
x2 – 4x + 5 = 0
(x – 5) (x + 1) = 0
x – 5 = 0 or x + 1 = 0
x = 5 or x = – 1
The value of x = -1 and 5
y2 – 2y = 8
y2 – 2y – 8 = 0
(y – 4) (y + 2) = 0
y – 4 = 0 or y + 2 = 0
y = 4 or y = -2
The value of y = -2 and 4
