<span>-2(2,7x-1)-(6-3,4x)+8(0,4x-2) = -5,4х + 2 - 6 + 3,4х + 3,2х - 16 = 1,2х -20
при х = -5/6
</span>1,2х -20 = 1,2 * (-5/6) - 20 = 6/5 * (-5/6) - 20 = -1 - 20 = -21
4x + 3y + 6 = 0, 8x + 6y - 7 = 0 → 4x + 3y - 7/2 = 0
|4x + 3y - 7/2 - (4x + 3y + 6)| = |-7/2 - 6| = 19/2
1)9x-10y+16x+9y
25x-1y=28(-0.8)-2.5=-22.5
2) -1.4a+31b-2.6a+4b
-4a+35b=-4*1.4+35(-0.2)=-12.6
1)3(x-15)+30-5x
3x-45+30-5x=-2x-15
2) -2(10+y)+19+3y
-20-2y+19+3y
-1+1y
627мм = 620 + 7 мм = 62 см + 7 мм
30, 60, 90
30:15=2
60:15=4
90:15=6