Your answer is 36. hope it helps!
Solution:
Using Substitution Method:
-4x+7y=-5 (Equation 1)
x-3y=-5 (Equation 2)
get the value of x from Equation 2
x=3y-5 (Equation 3)
Put the value of x from Equation 3 in Equation 1
-4(3y-5)+7y=-5
-4(3y)+20+7y=-5
-12y+7y=-5-20
-5y=-25
Negative sign on both sides cancels each other
y=25/5
y=5
Putting value of y in equation 3
x=3(5)-5
x=15-5
x=10
Therefore, [x,y]=[10,5]
Using Elimination Method
-4x+7y=-5 (Equation 1)
x-3y=-5 (Equation 2)
Multiply equation 2 with -4 in order to eliminate the x term
-4(x-3y)=-5*4
-4x+12y=20 (Equation 3)
Adding Equation 1 and 3
-4x+7y=-5
-4x+12y=20
+ - = - (Change Of Sign with x and y terms)
-----------------
0x-5y = -25
-5y=-25
y=5
Substituting y’s value is Equation 1
-4x+7(5)=-5
-4x+35=-5
-4x=-40
Cancellation of negative sign on both sides
x=40/4
x=10
[x,y]=[10,5]
