Question

independent practice: write equations in multiple variables practice* mr. johnson is deciding which chemicals to buy for his chemistry class. chemical a costs $5 per gram, chemical b costs $7 per gram, and chemical c costs $9 per gram. his budget for purchasing the chemicals is $300. create an equation using the variables a as the number of grams of chemical a, b as the number of grams of chemical b, and c as the number of grams of chemical c. use the keypad to enter your answer in the box. more symbols can be found using the drop - down arrow at the top of the keypad.

Explanation:

Step1: Calculate cost of Chemical A

The cost of Chemical A is $5$ dollars per gram and there are $a$ grams, so the total cost of Chemical A is $5a$ dollars.

Step2: Calculate cost of Chemical B

The cost of Chemical B is $7$ dollars per gram and there are $b$ grams, so the total cost of Chemical B is $7b$ dollars.

Step3: Calculate cost of Chemical C

The cost of Chemical C is $9$ dollars per gram and there are $c$ grams, so the total cost of Chemical C is $9c$ dollars.

Step4: Set - up the equation

The total budget is $300$ dollars. The sum of the costs of Chemical A, B and C should equal the budget. So, $5a + 7b + 9c=300$.

Answer:

$5a + 7b+9c = 300$