Answer: look at the picture
Step-by-step explanation: Hope this help :D
Answer:
I think it is the last one
Step-by-step explanatio
5x+7y=25
5x-2y=-65
subtract both of the equations
5x-5x=0
7y--2y= 7y+2y=9y
25--65=25+65=90
0+9y=90
9y=90
divide both sides by 9 to get y by itself
9y/9=90/9
cross out 9 and 9 which becomes 1*1*y=y
90/9=10
y=10
find x by using the substitution method
5x+7y=25
5x+7(10)=25
5x+70=25
move +70 to the other side
sign changes from +70 to -70
5x+70-70=25-70
5x=-45
divide both sides by 5 to get x by itself
5x/5=-45/5
cross out 5 and 5 then becomes 1*1*x=x
-45/5=-9
x=-9
answer:
(-9,10)
Answer:
x = 63 y = 27
Step-by-step explanation:
The straight line is 180 degrees
subtract 117 from 180 to get 63
It says x+7= 90, so subtract x(63) from 90 to get 27
Answer:
<em>The area of the triangle DEF is 10.</em>
Step-by-step explanation:
<u>Area of a Triangle:</u>
A triangle of base B and height H (both must be perpendicular) has an area of:

The image below shows the triangle formed by the points DEF. It's important to notice the points E and F lie on the same horizontal line because they both have the same y-coordinate.
This fact simplifies the calculations since we can easily compute the length the of base as the difference of their x-coordinates:
B=3-(-2)=3+2=5
Being the base of a horizontal line, the height of the triangle can be calculated as the difference of y-coordinates of D and the height of that line.
H=2-(-2)=4
With these two values, we calculate the area:

The area of the triangle DEF is 10.