Answer: 25x² - 64
<u>Step-by-step explanation:</u>
(5x + 8)(5x - 8)
= 5x(5x - 8) + 8(5x - 8)
= 25x² - 40x + 40x - 64
= 25x² + 0x - 64
= 
NOTE: descending powers means the biggest exponent goes first, then the next biggest exponent, etc.
For example: x⁴ then x³ then x² then x then the number (which is actually x⁰)
The length would be 18 inches and the width would be 9 inches since the length is twice its width and to find perimeter you do length x 2 and width x 2 and add it together so 18x2 = 36 and 9x2 = 18. 36 + 18 = 54
6/10 + 7/12 = 142/120 = 71/60 = 1.18 (One whole number, and 11/60)
2,475,000 this your answer
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%.
