2x + y = 20
-5y = -6x + 12
To use the substitution method, first isolate one of the variables in one of the equations.
Isolate the "y" in the first equation (because it is the easiest to isolate), and substitute it into the second equation:
2x + y = 20 Subtract 2x on both sides
y = 20 - 2x
-5y = -6x + 12 (since y = 20 - 2x, you can substitute 20 - 2x into y)
-5(20 - 2x) = -6x + 12 Multiply -5 into (20 - 2x)
-100 + 10x = -6x +12 Add 100 on both sides
10x = -6x + 112 Add 6x on both sides
16x = 112 Divide 16 on both sides
x = 7
Now that you have found x, you can substitute 7 into x for one of the original equations:
2x + y = 20
2(7) + y = 20
14 + y = 20 Subtract 14 on both sides
y = 6
-5y = -6x + 12
-5y = -6(7) + 12
-5y = -42 + 12
-5y = -30 Divide -5 on both sides
y = 6
x = 7, y = 6
Answer:
Jane drives at an average speed of 45 mph on a journey of 135 miles. How long ... by speed. 135 miles ÷ 45 mph = 3 hours ... of 8 mph. If he cycles for 6½ hours, how far does he travel? ... in 4 hours. (a) What is her average speed for the first part of the journey? ... (a) What is average speed of the car in miles per hour? mph.
Step-by-step explanation:
Answer:
A) The functions are not inverses of each other.
Step-by-step explanation:
The result of f(g(x)) is not always x, so the functions are not inverses of each other.
In general, a quadratic (or any even-degree polynomial) such as g(x) cannot have an inverse function because it does not pass the horizontal line test.
Whether it can be equal to that value. For example, if 5 is greater than x, then an open circle will be useful. If 5 is greater than or equal to x, a closed circle will be used.
