An unknown number b is 10 more than an unknown number k. the number b is also k less than 8. the equations to find k and b are shown below:

b = k + 10
b = −k + 8

which is a correct step to find k and b?
write the points where the graphs of the equations intersect the x-axis. write the points where the graphs of the equations intersect the y-axis. add the equations to eliminate k. multiply the equations to eliminate b.

Add the equations to eliminate k.

Step-by-step explanation:

When we add the equations we get

next we put into and solve for k:

this way we have found k and b; therefore, adding the equations to eliminate k is a correct step for finding k and b.

Let us now look at other choices we were given.

Write the points where the graphs of the equations intersect the x axis.

These points may be the solutions to each equation, but they are not the solutions to the system of these two equations.

Write the points where the graphs of the equations intersect the y axis.

Same thing goes here: these points may be the solutions to each equation, but they are not the solutions to the system of these two equations.

Multiply the equations to eliminate b.

Multiplying the equations doesn't eliminate b, but rather it complicates the matter by producing a quadratic equation—we don't want to go down that road!

step-by-step explanation:

a.   since the profit made in 2012 is equal to the profit made in 2014, the profit is           symmetric about the line y = 120,000.

step-by-step explanation:

given that megan owns a clothing boutique.

the profits of 2010, 11, are recorded and shown as follows:

years since     2010 0     1     2     3       4       5

profits made in 1000's   39       84     111     120   111     84

we find that profit gradually increases form 2010 to 2013 upto 120,   then starts decreasing.

the profits for 2012 and 2014 are the same while that of 2011 and 2015 are also the same.

this shows that there is symmetry about the line profit = 120000

hence answer is:

a.   since the profit made in 2012 is equal to the profit made in 2014, the profit is           symmetric about the line y = 120,000.

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