12. When Raphael solved the system below by using the method of elimination, he changed the second equation to-88-2y = -2. What property justifies this manipulation?
8x + 3y = 7
4x + y = 1

Cherie measures and records the lengths and sizes of the same style of a sandal found at a shoe store. which equation can be used to determine the approximate shoe size, s, for a foot length of x inches? s = x – 2 s = 2x – 10 s = x + 6 s = 2x + 4

Which mathematical statements are true? 1) if 3 is an odd number, then 3 times 3 is an even number. 2) if 6 is less than 7, then 4 is greater than 7. 3) six is divisible by 3, and 10 is a multiple of 2. 4) the average of the data is greater than the largest value in the data, or it’s less than the largest value in the data. 5) the slope of a linear graph is its rate of change, and the graph’s y-intercept is the initial value. 6) if an equilateral triangle has equal angles, then all its angles will measure 45°.

Of the ones listed here, the factor that had the greatest impact on the eventual destruction of native americans' ways of life was the development of the a) automobile. b) highway. c) railroad. d) steamboat.