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Question

Question: How do you graph \[y = 5x - 2?\]...

How do you graph y=5x2?y = 5x - 2?

Explanation

Solution

The given question describes the operation of addition/ subtraction/ multiplication/ division. Also, this problem involves substituting the xx values in the given equation to find the value yy. Also, yy is the function of xx. By using xx and yy values we can easily draw the graph for the given equation. We have to assume the value xx for solving the given question.

Complete step by step solution:
The given equation is shown below,
y=5x2(1)y = 5x - 2 \to \left( 1 \right)
We would draw the graph for the above equation. As a first step, we would assume the xx value as given below,
x=.......2,1,0,1,2,.......x = ....... - 2, - 1,0,1,2,.......
Let’s substitute x=2x = - 2 in the equation (1)\left( 1 \right), we get

(1)y=5x2 y=(5×2)2 y=102 y=12 \left( 1 \right) \to y = 5x - 2 \\\ y = \left( {5 \times - 2} \right) - 2 \\\ y = - 10 - 2 \\\ y = - 12 \\\

Let’s substitutex=1x = - 1 in the equation (1)\left( 1 \right), we get

(1)y=5x2 y=(5×1)2 y=52 y=7 \left( 1 \right) \to y = 5x - 2 \\\ y = \left( {5 \times - 1} \right) - 2 \\\ y = - 5 - 2 \\\ y = - 7 \\\

Let’s substitute x=0x = 0 in the equation (1)\left( 1 \right), we get

(1)y=5x2 y=(5×0)2 y=2 \left( 1 \right) \to y = 5x - 2 \\\ y = \left( {5 \times 0} \right) - 2 \\\ y = - 2 \\\

Let’s substitute x=1x = 1 in the equation (1)\left( 1 \right), we get
(1)y=5x2\left( 1 \right) \to y = 5x - 2

y=(5×1)2 y=52 y=3 y = \left( {5 \times 1} \right) - 2 \\\ y = 5 - 2 \\\ y = 3 \\\

Let’s substitute x=2x = 2 in the equation (1)\left( 1 \right), we get

(1)y=5x2 y=(5×2)2 y=102 y=8 \left( 1 \right) \to y = 5x - 2 \\\ y = \left( {5 \times 2} \right) - 2 \\\ y = 10 - 2 \\\ y = 8 \\\

Let’s make a tabular column by using the xx and yy values,

xx2 - 21 - 1001122
yy12 - 127 - 72 - 23388

By using this table we can easily draw the following graph,


The above figure represents the equation y=5x2y = 5x - 2

Note: This type of question involves the operation of addition/ subtraction/ multiplication/ division. In this type of question, we would assume the xx value, by using the xx value we can easily find the yy values. Note that the graph would be based on the equation of yy. yy is the function of xx so, yy can also be written as f(x)f\left( x \right). When multiplying the different sign numbers remember the following things,

  1. When a negative number is multiplied with the negative number the answer becomes a
    positive number
  2. When a positive number is multiplied with the positive number the answer becomes a
    positive number.
  3. When a positive number is multiplied with the negative number the answer becomes a
    negative number.