Question

упростить выражение (4х-3)2х-(2х+1)(3х-2)2х при х=0,7​

Answer 1

$(4x - 3) \times 2x - (2x + 1)(3x - 2) \times 2x = 8 {x}^{2} - 6x - (6 {x}^{2} - 4x + 3x - 2) \times 2x = 8 {x}^{2} - 6x -(12 {x}^{3} - 8 {x}^{2} + 6 {x}^{2} - 4x) = 8 {x}^{2} - 6x - (12 {x}^{3} - 2 {x}^{2} - 4x) = 8 {x}^{2} - 6x -12 {x}^{3} + 2 {x}^{2} + 4x = - 12 {x}^{3} + 10 {x}^{2} - 2x = - 2x(6 {x}^{2} - 5x + 1)$

при х=0,7

$- 2 \times 0.7(6 \times {0.7}^{2} - 5 \times 0.7 + 1) = - 1.4(2.94 - 3.5 - 1) = - 1.4 \times 0.44 = - 0.616$