Find two numbers whose sum is 15; twice the first number decreased by the second number gives 6.
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Answer:
Step-by-step explanation:
Perform the multiplication and addition:
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<em>Comment on the squaring</em>
There are several ways you can find the square (x+4)².
- Use your knowledge that (x+a)² = x²+2ax+a².
- Use FOIL* to compute (x+4)(x+4) = x² +4x +4x +4² = x²+8x+16
- Use the distributive property: (x+4)(x+4) = x(x+4) +4(x+4) = x² +4x +4x +4² (same as FOIL for two binomials)
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* FOIL is mnemonic for {First, Outer, Inner, Last} referring to pairs of terms in the factors (x +a)(x +b). The x terms are the First terms. The Outer terms are the first x and b. The Inner terms are "a" and the second x. The Last terms are "a" and "b". You are to form the sum of those pairs of terms to find the product of the binomials.
