1) x + 2y = -7 and 5x – 3y = 30
By substitution method:
Step 1. Find an equation to be used as a substitute to the other equation.
x + 2y = -7 –> x = -7 – 2y
Step 2. Substitute the equation to the other equation.
x = -7 – 2y
5x – 3y = 30
5 (-7 – 2y) – 3y = 30
-35 – 10y – 3y = 30
-10y – 3y = 30 + 35
-13y = 65 Divide by -13
y = -5
Step 3. Substitute -5 to y and solve the other variable.
x = -7 – 2y
x = -7 – 2(-5)
x = -7 + 10
x = 3
Step 4. Check
(3, -5)
x + 2y = -7 l 5x – 3y = 30
3 + 2(-5) = -7 l 5(3) – 3(-5) = 30
3 – 10 = -7 l 15 + 15 = 30
- 7 = – 7 l 30 = 30
Therefore the solution is (3, -5).
IF YOU HAVE ANY QUESTION JUST PUT A COMMENT IN THIS POST..TNX
-MR. GONZALES
