Solve the following systems of equation for x and y. Show your work on how you solved for x and y
1. −4x − 2y = −12
4x + 8y = −24

2. x − y = 11
2x + y = 19

3. 5x + y = 9
10x − 7y = −18

4. −3x + 7y = −16
−9x + 5y = 16

5. −7x + y = −19
−2x + 3y = −19

6. 5x + 4y = −30
3x − 9y = −18

7. −4x + y = 6
−5x − y = 21

The length of a rectangle plus its width is 25 cm. the area is 156 square cm. what are the length and width of the rectangle? separate the answers with a comma.

Needmax recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.