Question

4/9(2.7a-2 1/4b)-4.2(5/7 a-0.5b)

Answer 1

4/9*(2,7- 2 1/4b)-4.2*(5/7у-0.5b)= 4/9*27/10-4/9*9/4b-42/10*5/7у+42/10*5/10= 6/5-b-3у+21/10=1,2-b-3у+2,1= 3,3-b-3у

Answer 2

⁴/₉(2,7a-2¹/₄b)-4,2(⁵/₇ a-0,5b) = 1,1b -1,8a
⁴/₉(2,7a-2¹/₄b) =⁴/₉×(²⁷/₁₀a-⁹/₄b) = ²⁷ˣ⁴/₁₀ₓ₉a-⁹ˣ⁴/₄ₓ₉b = ¹²/₁₀a - b = 1,2a - b
4,2(⁵/₇ a-0,5b) =⁴²/₁₀×(⁵/₇ a-⁵/₁₀b) =⁴²/₁₀×⁵/₇ a-⁴²/₁₀×⁵/₁₀b= ⁴²ˣ⁵/₁₀ₓ₇a - ⁴²ˣ⁵/₁₀ₓ₁₀b = ⁶/₂a-²¹/₁₀b = 3a - 2,1b
(1,2a - b) - (3a - 2,1b) = 1,2a - b - 3a + 2,1b = 1,1b -1,8a