Write the expression in words! 5x + 3

The expression 5x+3 would be three more than five times a number! More than in this case would be addition - so if you get the same problem with subtraction you just change more to less!
Basically what it's tell you is that if x stood for 2 in this case 5*2 = 10 since it's 3 MORE than 5 times a number (x is in place of a number), you're adding 3 to 10 and that gives you 13!
I hope I simplified it a little more and you understand!
Good luck, rockstar! c: I hope this helped!

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.