Solve each system by substitution. 8). -7x-2y=-13 x-2y=11

-7x-2y=-13
x-2y = 11 get x alone
x-2y+2y=11+2y
x= 2y+11 substitute into 1st equation

-7 (2y+11) -2y =-13
-14y -77 -2y = -13
-16y -77 = -13
-16y -77 + 77 = -13 + 77
-16y = 64
-16y/-16 = 64/-16
y = -4

substitute in the 2nd equation

x =2y +11
x = 2(-4) + 11
x = -3 + 11
x = 3

Check work
-7(3) -2(-4) = -13
-21 + 8 = -13
-13 = -13

3 -2(-4) = 11
3 + 8 = 11
11 = 11

(See explanation)

Step-by-step explanation:

The differential equation for a exponential growth is:

The formula is rearranged and integrated afterwards:

The exponential growth function can be used to find the montly growth function as follows:

The coeffcients of the expression are, respectively:

The exponential growth function with a monthly growth rate is:

, where t is measured in months.