Question

-(4,5х-3,8у+5)+(1,5х+0,2у-4) , если х=-0,4 ; у=-0,5
б)
(3,5х-3,7у-5)- (1,5х+0,3у+4) , если х=-0,5 ; у=-0,3​

Answer 1

Ответ:

1.

$- (4.5x - 3.8y + 5) + (1.5x + 0.2y - 4) = - 4.5x + 3.8y - 5 + 1.5x + 0.2y - 4 = - 3x + 4y - 9$

$x = - 0.4 \\ y = - 0.5$

$- 3x + 4y - 9 = - 3 \times ( - 0.4) + 4 \times ( - 0.5) - 9 = 1.2 - 2 - 9 = - 9.8$

2.

$(3.5x - 3.7y - 5) - (1.5x + 0.3y + 4) = 3.5x - 3.7y - 5 - 1.5x - 0.3y - 4 = 2x - 4y - 9$

$x = - 0.5 \\ y = - 0.3$

$2x - 4y - 9 = 2 \times ( - 0.5) - 4 \times ( - 0.3) - 9 = - 1 + 1.2 - 9 = - 8.8$