Please help.
Algebra.

 (x,y) = (6,-3)

This means 6 goes in the first blank and -3 goes in the second blank.

Explanation:

Solve the second equation for x

x+8y = -18

x = -18-8y

We'll plug that into the first equation and isolate y. This is where substitution comes in.  

5x + 7y = 9

5( x ) + 7y = 9

5( -18-8y ) + 7y = 9 ... replace x with -18-8y

-90-40y + 7y = 9

-90-33y = 9

-33y = 9+90

-33y = 99

y = 99/(-33)

y = -3

Use this y value to find x

x = -18-8y

x = -18-8(-3)

x = -18+24

x = 6

The solution is (x,y) = (6,-3)

Checking the

Let's check the first equation

5x+7y = 9

5(6)+7(-3) = 9 ... plug in (x,y) = (6,-3)

30-21 = 9

9 = 9 true equation

Do the same for the second equation as well

x+8y = -18

6 + 8(-3) = -18

6 - 24 = -18

-18 = -18 also true

Both equations are true when we plug in (x,y) = (6,-3), so the solution is confirmed.

i pretty sure it is

pentagon

step-by-step explanation:

the coordinates   a(5, -2), b(3,-1),c(-4,-4) d(-3,8) and e(-1,4) forms the vertices of the polygon when they are connected in order.

in order to classify that which polygon is it with the given coordinates, first count the number of vertices and then count the number of sides it can make with these vertices.

since, the given coordinates have five vertices, therefore, it will make five sides. moreover, pentagon is regular in nature therefore it will be convex.

now, a polygon with five sides is known as pentagon, therefore, the given polygon is the pentagon.