6*(2a-7)+4*(5a-6) при a=-2,5

6 * (2a - 7) + 4 * (5a - 6) = ? при a=-2,5Решение: 6 * (2a - 7) + 4 * (5a - 6) = 12a - 42 + 20a - 24 = a(12 + 20) + (- 42 - 24) = 32a - 66a = -2,532 * (-2,5) - 66 = 32 * (-2 5/10) - 66 = 32 * (- 25/10) - 66 = 32 * (- 5/2) - 66 = - (32 * 5/2) - 66 = - (5 * 32/2) - 66 =- (5 * 16) - 66 = -80 - 66 = - (80 + 66) = -146Ответ: -146