Use double angle identity

We can relate '6x' to '3x' in the same way since 6 is 2*3.

Now sub into left side of identity. Simplify until it equals right side.
Answer:
B. $36.25+$3.89x≤$58.50
Step-by-step explanation:
It has to be less than or equal to $58.50
This equation in word form would be 7x -6 = -20, and the solution to that equation is x = -2
Answer:
The first equation should be multiplied by 9 and the second equation by −4
Step-by-step explanation:
Given the simultaneous equation
First Equation: 5x − 4y = 28
Second equation: 3x - 9y = 30
In order to eliminate y, we must make the coefficient of x in both expression to be equal.
To do that the first equation should be multiplied by 9 (negative value of the coefficient of y in equation 2)and the second equation by -4( (coefficient of y in equation 1)