Step-by-step explanation:
For the quadratic equation to have 1 repeated real solution, the discriminant b² - 4ac must be zero.
=> (-z)² - 4(z - 5)(5) = 0
=> z² - 20(z - 5) = 0
=> z² - 20z + 100 = 0
=> (z - 10)² = 0
Therefore z = 10.
Answer: 1999 perfect squares between 1,000,000 and 9,000,00
Step-by-step explanation:
Sq root of 1,000,000 is 1000 and square root of 9,000,000 is 3000
Hence there are squares of 1001 to 2999 I. e. 1999 perfect squares between 1,000,000 and 9,000,00
Answer:
Step-by-step explanation:
Given
Required
Determine the percentage of the shaded cubes
First, we calculate the number of boxes:
Express as multiplication
This implies that there are 20 cubes in the box.
The percentage of the shaded cubes is:
<em>30% were shaded</em>
Answer:
3
Step-by-step explanation:
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With amounts measured in gallons, let
x = amount of 65% antifreeze
y = amount of 90% antifreeze
1 gal of the 65% brand contains 0.65 gal of pure antifreeze; x gal would contain 0.65x gal. Similarly, y gal of the 90% brand contains 0.90y gal of pure antifreeze.
To obtain 120 gal of 80% antifreeze solution (which contains 0.80•120 = 96 gal of pure antifreeze), we must have
x + y = 120 … … … … … [total volume of antifreeze solution]
0.65x + 0.90y = 96 … [total volume of pure antifreeze]
Solve the first equation for y :
y = 120 - x
Substitute this into the second equation and solve for x :
0.65x + 0.90 (120 - x) = 96
0.65x + 108 - 0.90x = 96
0.25x = 12
x = 48
Solve for y :
y = 120 - 48
y = 72
