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It is known that the solution of the system of equations ax + by = 3bx + ay = 7 is x = 2Y = 1, then the value of a + B is () A. 3B. -3C. 103D. −103
Substituting x = 2, y = 1 into the equations, 2A + B = 3, ① 2B + a = 7, ②, ① + ②: 3 (a + b) = 10, then a + B = 103
The solution of x = 2 y = - 1 system ax + 2Y = 1 4x-y = 2b-1 to find the value of a and B
That's not right
ax+2y=1
2a-2=1
a=3/2
4x-y=2b-1
8+1=2b-1
b=5
It is known that the symmetry axis of the image of the quadratic function y = x ^ 2 + BX + C is x = - 1, and the minimum value is - 14. The approximate root of the equation x ^ 2 + BX + C = 0 is obtained by using the image of the function
The axis of symmetry is x = - B / 2, so B = 2
The minimum value is (4c-b & # 178;) / 4 = (4c-4) / 4 = - 14
So C = - 13
y=x²+2x-13
x²+2x-13=0
(x+1)²=14
So x = √ 14-1 or - √ 14-1
The approximate value is 14
√14≈3.74
We can increase our knowledge and writing ability by reading extracurricular books
Reading extracurricular books can increase our knowledge and improve our writing level
To judge whether a year is a leap year or an ordinary year, how to calculate it?
In general, the year that can be divided by four is leap year, and the year that cannot be divided by four is ordinary year. For example, in 1988, 2008 is leap year; in 2005, 2006, 2007 is ordinary year. But if it is century year (that is, the whole century year), only the year that can be divided by 400 is leap year, otherwise it is ordinary year. For example, 2000 is leap year, and 1900 is ordinary year
February in leap year has 29 days, while February in ordinary year has only 28 days
X divided by three eighths is ten twenty-one times fourteen fifteen to find the unknown
x÷8/3=21/10×15/14
x=21/10×15/14×8/3
x=6/1
1. Xiao gang saw a story book. He read 56 pages every day. After 4 days, he just read 11:3. How many pages are there? How many pages are left?
2. A bus from place a to place B runs one fifth of the whole journey on the first day and 450km on the second day. At this time, the ratio of the distance traveled and the rest of the journey is 3:7. What is the distance?
After answering both questions, tell me why,
1. Xiao gang saw a story book. He read 56 pages every day. After four days, he just read three out of eleven. How many pages are there? How many pages are left?
Hello, hello,
1: A total of 56 * 4 △ 8 / 11 = 308 pages, 308-56 * 4 = 84 pages left
2: The ratio of the distance traveled to the rest is 3:7, 3 / (3 + 7) = 3 / 10
The whole course is 450 △ 3 / 10-1 / 5 = 450 △ 1 / 10 = 4500km
”Children need love?
children require love.require It's more advanced than need
Express 2.36 degrees in degrees, minutes and seconds
2.36°,141.6＇,141.6＂
A sealed rectangular glass jar is 50 cm long, 30 cm wide, 20 cm high and 10 cm deep. If the glass jar is erected to the right, how many cm deep is it?
50 × 30 × 10 ^ (30 × 20), = 15000 ^ 600, = 25 (CM), a: This is the water depth of 25 cm
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