Chen uses mental math to find the sum of 326 and 24. She uses 320, 24, and one other number. What is the missing number?
1 answer:
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Answer:
x = 3, -2
Step-by-step explanation:
To help us factor, we can split the middle term up into the sum of the terms -3x and 2x:
From there, we can factor out an x from the first two term and a 2 from the last two to obtain the equation
Factoring out an (x - 3) from each term gives us the equation
At this point, we can divide by either x - 3 or x + 2 to obtain the two equations
and
Solving both for x gives us the solutions x = 3 and x = -2. We can verify these by substituting them back into the original equation: