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Equation
−4(10 − a) = 36 Simplify both sides
(−4)(10) + (−4)(−a) = 36 Distribute
−40 + 4a = 36
4a − 40 = 36
4a - 40 + 40 = 36 + 40 Add 40 to both sides
4a = 76
4a/4 = 76/4 Divide both sides by 4
76/4 = 19 Simplify 76/4
a = 19
Hope this helps!
When you say "at the same ratio", you mean that you consume the same amount of gas for the same amount of miles.
We know that everytime you drive 75 miles, you use 3 gallons of gas.
Since 12 gallons of gas is four times 3 gallons of gas, if the ratio remains the same, you can drive four times the distance:
You drive 75 miles, and use 3 gallons.
You drive 75 more miles (so you are at miles) and use 3 more gallons, so you use
gallons.
You drive 75 more miles (so you are at miles) and use 3 more gallons, so you use
gallons.
You drive 75 more miles (so you are at miles) and use 3 more gallons, so you use
gallons, and you're done.