Answer:
(-12,11)
Step-by-step explanation:
x + 2y = 10
3x + 4y = 8
(-2)x + (-2)2y = (-2)10
3x + 4y = 8
-2x - 4y = -20
3x + 4y = 8
Add to eliminate:
x = -12
Substitute x to solve y:
x + 2y = 10
(-12) + 2y = 10
-12 + 2y = 10
2y = 10 + 12
2y = 22
y = 22 ÷ 2
y = 11
Check:
x + 2y = 10
(-12) + 2(11) = 10
-12 + 22 = 10
10 = 10
Answer:

Step-by-step explanation:
we know that
The formula to find the sum is equal to

where
a1 is the first term
an is the last term
n is the number of terms
In this problem we have



substitute the values in the formula

We know that 2x + 5 = 10 - 3x, and because of this we can solve for x.
2x + 5 = 10 - 3x
+3x
5x + 5 = 10
-5
5x = 5
/5
x = 1
We can plug x into each x value to verify if this is true.
2(1) + 5 = 10 - 3(1)
2 + 5 = 10 - 3
7 = 7