This is the "empirical rule." Approx. 68% of a data set lie within one standard deviation of the mean.
Answer:
40
Step-by-step explanation:
2 • (3(5 + 2) - 1) =
Start with the innermost parentheses.
= 2 • (3(7) - 1)
Now do the multiplication inside the parentheses.
= 2 • (21 - 1)
Do the subtraction inside the parentheses.
= 2 • 20
= 40
Length of the outer frame: 4+2x
width of the outer frame: 3+2x
area of the outframe: (4+2x)(3+2x)=15
expand the equation: 12+8x+6x+12x^2=15
combine like terms: 4x^2+14x-3=0
