Question

1. If the values of a + b and a - b are
7 and 4 respectively, find the values
of a² + b2 and ab.​

Answer 1

Answer:

Step-by-step explanation:

a + b =7 (1)

a - b =4. (2)

Add equation (1) and (2) we get

2a =11

a =11/2

Substitute value of a in (1)

11/2 + b = 7

b = 7 - 11/2

b = (14 - 11)/2 = 3/2

a^2 = (11/2)^2 = 121/4

b^2 = ((3/2)^2 = 9/4

Hence a^2 +b^2 = 121/4 + 9/4 = 130/4

= 65/2

ab = 11/2 × 3/2

= 33/4

Hope it is clear

Answer 2

Step-by-step explanation:

I)(asqu + bsqu) (asqu - bsqu) = asqu- bsqu

by this formula

(7) squ - (4)squ

49 -16

33

ii)a squ + bsqu = (a+b) the whole squ

by this formula

(7+4) the whole squ

49 + (2) (7)(4) + 16

49+ (14 ) (4) +16

49 + 56 +16

121

iii) (7 )(4)

28