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Answer:
Step-by-step explanation:
<h3>to understand this</h3><h3>you need to know about:</h3>- factoring
- PEMDAS
- quadratic expression:ax²+bx+c
factoring quadratic:
- Find two numbers that multiply to give ac, and add to give b
- rewrite the middle with those numbers
- factor out common terms
- group
a is 3 and b is -7
therefore
now we need to find two numbers that give -21
to do so we need to find the factors of 21
which are
likewise,
in this case we can take any two numbers from negative and positive factors that give us -21 and -4
3 and -7 are the two numbers that multiply to give -21 (3×-7=-21) and add to give -4. (3+(-7)=-4)
now let's factor: