Question

. If a = 2 and b = –1, then find the values of the following algebraic
expressions.

a. a + b – 2ab
b. 5a + a3
– 15b​

Answer 1

a = 2 and b = –1

a) a + b – 2ab

2 + (-1) -2×2×-1

2 -1 +4

= 5

b) 5a + a³

5×2 + 2³

= 10 +8

=18

c) -15b

-15 × -1

= 15

Answer 2

Given ,

a = 2

b = -1

1) a+b - 2ab

2 +(-1) - 2 × 2 × (-1)

2- 1 +4

1+4

5

2) 5a + a^3 - 15b

5 × 2 + 2^3 - 15 × (-1)

10 + 8 + 15

33