Which polynomial is the perfect square trinomial? And why??? Help Please!!
1 answer:
<h3>Answer:</h3>
See the attached
<h3>Step-by-step explanation:</h3>When you square the binomial (a -b), you get ...
... (a -b)² = a² -2ab +b²
That is, both the a² and b² terms have positive signs, and the middle term is twice the product of the roots of the squared terms.
The last two selections have negative signs on the constant, so cannot be perfect square trinomials.
The first selection has a middle term that is -ab, not -2ab, so it is not a perfect square trinomial, either.
The second selection is the correct one:
... 4a² -20a +25 = (2a +5)²
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Try, please, this:
1) Imagine, that pharmacist used 'x' gr. of 40% solution and 'y' of 70% solution.
Together (20 gr. of 52% sol.) it will be x+y=20.
2) From other side, the pharmacist combined 40x and 70y gramms, after obtaining together it is 52(x+y) gramms. In other words 40x+70y=52(x+y)
3)
Answer: 8 gr. of 70% solution and 12 gr. of 40%.
1) Imagine, that pharmacist used 'x' gr. of 40% solution and 'y' of 70% solution.
Together (20 gr. of 52% sol.) it will be x+y=20.
2) From other side, the pharmacist combined 40x and 70y gramms, after obtaining together it is 52(x+y) gramms. In other words 40x+70y=52(x+y)
3)
Answer: 8 gr. of 70% solution and 12 gr. of 40%.