I need help to answer/ solve this What is the first step for solving this system of equations using the SUBSTITUTION method?
x - 2y = 8
x = 5 - y

Step-by-step explanation:

Solve by Substitution :

// Solve equation [2] for the variable  y

[2]    y = -x + 5

// Plug this in for variable  y  in equation [1]

  [1]    x - 2•(-x +5) = 8

  [1]    3x = 18

// Solve equation [1] for the variable  x

[1]    3x = 18

[1]    x = 6

// By now we know this much :

   x = 6

   y = -x+5

// Use the  x  value to solve for  y

  y = -(6)+5 = -1

Solution :

The answer is in the image 

The solution is in the following image

The answer is in the image 

The answer is in the image 

Speed=Distance/time

Here,

distance=15m

time=1sec

speed=15/1=15m/sec

Distance=Speed*time

time=15min=15*60sec=900sec

Distance travelled in 15 min=15*900=13,500m

=13500/1000 km=13.5Km

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

Let the father's age be x and son's be y

10 years before-

Father age=x-10

sons age=y-10

Given,

x-10=10(y-10)

x-10=10y-100

Given present age of father=40

therefore,

x=40

40-10=10y-100

10y-100=30

10y=130

y=130/10

y=13

Therefore present age of son=13years

Given height of gymnasium is 5/6 height of 30 foot ball

therefore height of gymnasium=5/6 * 30

=25 feet