How did the completion on the transcontinental railroad affect companies that yes made products?

simplify brackets

8 - 2a - 7 = a + 40

simplify 8 - 2a - 7 to -2a + 1

-2a + 1 = a + 40

add 2a to both sides

1 = a + 40 + 2a

simplify a + 40 + 2a to 3a + 40

1 = 3a + 40

subtract 40 from both sides

1 - 40 = 3a

simplify 1 - 40 o -39

-39 = 3a

divide both sides by 3

-39/3 = a

simplify 39/3 to 13

-13 = a

switch sides

a = -13

incident infrared radiation is blocked. visible and ultraviolet radiation heat   earth.

earth radiates infrared radiation. infrared radiation is blocked and heats earth. visible and shortwave radiation heat earth.

earth radiates longwave radiation

longwave radiation is reflected downward longwave radiation heats earth