Question

3 1384. Знайди корiнь рiвняння: 1) 2(0,2x - 3) - 8(0,7x - 4) = 39; 2) 3,2(23y) = 3(0,8y − 1) + 3,4;​

Answer 1

$2(0.2x - 3) - 8(0.7x - 4)= 39 \\ 0.4x - 6 - 5.6x + 32 = 39 \\ - 5.2x = 39 - 26 \\ - 5.2x = 13 \\ x = 13 \div ( - 5.2) \\ x = 130 \div ( - 52) \\ x = - 2.5$

$3.2(2 - 3y) = 3(0.8y - 1) + 3.4 \\ 6.4 - 9.6y = 2.4y - 3 + 3.4 \\ 2.4y + 9.6y = 6.4 - 0.4 \\ 12y = 6 \\ y = 6 \div 12 \\ y = 0.5$