Pls solve it as fast as possible

Factor by finding the GCF: 2x - 4y + 6

What number should be added to both sides of the equation to complete this square? x^2-10x=7

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

The diagram shows corresponding lengths in two similar figures. find the area of the smaller figure. a. 14.4 yd2 b. 24 yd2 c. 26.4 yd2 d. 28