2 Why is adding 6, 10, and 5 to a number the same as
adding 21 to that number?

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.

To find the x-intercept, make  y  equal to zero, and solve for  x. to find the y-intercept, make  x  equal to zero, and solve for  y.explanation: y=4x−2x-intercept0=4x−2add  2  to both sides of the equation.2=4xdivide both sides by  4.24=xsimplify.12=xswitch sides.x=12y-intercepty=4(0)−2y=−2