Justify each step in solving the equation 4x = 7(x-3) by writing a reason for each statement
1 answer:
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Answer/Step-by-step explanation:
Equation to represent the daily rental cost for each type of truck can be written as follows:
Daily rental cost for Trucks-A-Lot = 42 + 0.72m
Daily rental cost for Move-in-Truckers = 70 + 0.12m
Where, m = Emily's mileage
To determine the number of miles for which the truck cost the same amount, set both equations equal to each other and solve for m.
Collect like terms
Divide both sides by 0.6
At approximately 47 miles, both trucks would cost the same amount.
Check:
Daily rental cost for Trucks-A-Lot = 42 + 0.72m
Plug in the value of x = 47
= 42 + 0.72(47) = $75.84 ≈ $76
Daily rental cost for Move-in-Truckers = 70 + 0.12m
Plug in the value of x = 47
= 70 + 0.12(47) = $75.64 ≈ $76
Answer:
(negative 7 x + 4)(negative 7 x minus 4)
Step-by-step explanation:
Consider two real numbers a and b. A difference of squares involving a and b is usually given as;
The difference of the two squares above can be factored to yield;
This implies that in order to have the difference of squares we must have a product involving the difference and the sum of the numbers.
The expression;
(negative 7 x + 4)(negative 7 x minus 4) can also be written as ( 4 - 7x) ( -4 - 7x)
( 4 - 7x) ( -4 - 7x) = ( 4 - 7x) (-1( 4 + 7x)) = -1 *( 4 - 7x) ( 4 + 7x)
Expanding the last expression yields;
-1 (16 + 28x -28x - 49x^2) = -1 (16 - 49x^2) = 49x^2 - 16 which is in deed a difference of squares