So x + y = 45, and 4x + 5y = 195. Get y by itself. Subtract x from both sides in the first equation to get y = 45 -x, and subtract 4x from the second equation to get 5y = 195 - 4x. Divide by 5 to both sides to get y = 39 - 4/5x. 39 - 4/5x = 45 - x. Add x to both sides to get 39 - 1/5x = 45. Subtract 39 from both sides to get -1/5x = 6. Divide by -1/5 to get x = -30, or 30. In the first equation, do 30 + y = 45. Subtract 30 from both sides to get y = 15. Check. 4(30) + 15(5) = 195, or 120 + 75 = 195.
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Answer:
a = 36 and a = 27
Step-by-step explanation:
The geometric mean of two numbers is the square root of the product of the two numbers.
Say for example we have the numbers x and y, the geometric mean z is mathematically;
z = √xy
For the first question, our z is 12, x and y are 4 and a respectively.
12 = √4a
square both sides
144 = 4a
a = 144/4
a = 36
For the second question
z is 9, x and y are 3 and a respectively
9 = √3a
square both sides
81 = 3a
a = 81/3
a = 27
