Y = 1/3x ? 6....slope here is 1/3. A perpendicular line will have a negative reciprocal slope. All that means is " flip " the slope and change the sign. So our perpendicular line will have a slope of -3 (see how I flipped 1/3 and changed the sign)
y = mx + b
slope(m) = -3
(-9,12)...x = -9 and y = 12
now we sub and find b, the y int
12 = -3(-9) + b
12 = 27 + b
12 - 27 = b
-15 = b
so ur perpendicular equation is : y = -3x - 15
Step 1:
Solve one of the equations for either x = or y = .
Step 2:
Substitute the solution from step 1 into the other equation.
Step 3:
Solve this new equation.
Step 4:
Solve for the second variable.
Example 1: Solve the following system by substitution
Substitution Method Example
Solution:
Step 1: Solve one of the equations for either x = or y = . We will solve second equation for y.
solution step 1
Step 2: Substitute the solution from step 1 into the second equation.
solution step 2
Step 3: Solve this new equation.
solution step 3
Step 4: Solve for the second variable
solution step 4
The solution is: (x, y) = (10, -5)
Hope this helps!
Multiply all of the numbers together: 5 x 2 x 8 = 10 x 8 = 80 ways
