Mathematics
Find the value of:
(i) 3x + 2y when x = 3 and y = 2
(ii) 5x - 3y when x = 2 and y = 5
(iii) a + 2b - 5c when a = 2, b = 3 and c = 1
(iv) 2p + 3q + 4r + pqr when p = 1, q = 2 and r = 3
(v) 3ab + 4bc - 5ca when a = 4, b = 5 and c = 2
Answer
(i) Substituting x = 3 and y = 2 in the given expression, we get:
3x + 2y
= 3(3) + 2(2)
= 9 + 4
∴ 3x + 2y = 13
(ii) Substituting x = 2 and y = 5 in the given expression, we get:
5x - 3y
= 5(2) - 3(5)
= 10 - 15
∴ 5x - 3y = -5
(iii) Substituting a = 2, b = 3 and c = 1 in the given expression, we get:
a + 2b - 5c
= 2 + 2(3) - 5(1)
= 2 + 6 - 5
∴ a + 2b - 5c = 3
(iv) Substituting p = 1, q = 2 and r = 3 in the given expression, we get:
2p + 3q + 4r + pqr
= 2(1) + 3(2) + 4(3) + (1)(2)(3)
= 2 + 6 + 12 + 6
∴ 2p + 3q + 4r + pqr = 26
(v) Substituting a = 4, b = 5 and c = 2 in the given expression, we get:
3ab + 4bc - 5ca
= 3(4)(5) + 4(5)(2) - 5(2)(4)
= 60 + 40 - 40
∴ 3ab + 4bc - 5ca = 60
Related Questions
Multiply:
(a) 5 × b
(b) x × y
(c) 2a × 3b
(d) a × a
(e) 6a × 2a
Divide:
(a) 12x ÷ 2x
(b) 24ab ÷ 8a
(c) 9x ÷ 3y
(d) 25a2 ÷ 5a
(e) 49xy ÷ 7xy
Find the value of:
(i) 2x2 - 3x + 4 when x = 2
(ii) 4x3 - 5x2 - 6x + 7 when x = 3
(iii) 3x3 + 9x2 - x + 8 when x = 4
(iv) 2x4 - 5x3 + 7x - 3 when x = 2
If x = 5, find the values of:
(i) 6 - 7x2
(ii) 3x2 + 8x - 10
(iii) 2x3 - 4x2 - 6x + 25