Which property of addition is used in the expression?
0.5+ (0.4+0.8) = (0.5 +0.4) + 0.8

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.

Titus works at a hotel. part of his job is to keep the complimentary pitcher of water at least half full and always with ice. when he starts his shift, the water level shows 4 gallons, or 128 cups of water. as the shift progresses, he records the level of the water every 10 minutes. after 2 hours, he uses a regression calculator to compute an equation for the decrease in water. his equation is w –0.414t + 129.549, where t is the number of minutes and w is the level of water. according to the equation, after about how many minutes would the water level be less than or equal to 64 cups?