Answer:
21.
Step-by-step explanation:
Since there were five teams entered in a competition, and each team consisted of either only boys or only girls, with the number of team members being 9, 15, 17, 19 and 21 members, if after one team of girls had been knocked out of the competition, the number of girls still competing was three times the number of boys, to determine how many girls were in the team that was eliminated, the following calculation must be performed:
9 + 15 + 17 + 19 = 60/4 = 15
9 + 15 + 17 + 21 = 62/4 = 15.5
9 + 15 + 19 + 21 = 64/4 = 16
9 + 17 + 19 + 21 = 66/4 = 16.5
15 + 17 + 19 + 21 = 72/4 = 18
Thus, since 15 x 3 equals 45, and 45 plus 15 equals 60, the number of girls on the team that was eliminated was 21.
eq^2: 7x=84 divide 84 by 7 which is 12.
therefore x is equal to 12. Then
1) take that 12 you got in equation 2 and substitute in equation 1 which is:
7x-12y=180
7(12)-12y=180
84 -12y=180
-12y=180-84
-12y=96 ............divide both sides with -12
-y=8 (×-1) both sides
y= -8
therefore 7(12)-12(-8)=180
Recall that the slope or gradient of a line segment through two points is the ratio of the change in the <em>y</em> coordinate to the change in the <em>x</em> coordinate.
If the gradient is 1, then
1 = (-3 - 4) / (<em>a</em> - 3<em>a</em>)
Solve for <em>a</em> :
1 = -7 / (-2<em>a</em>)
1 = 7/(2<em>a</em>)
2<em>a</em> = 7
<em>a</em> = 7/2
