单选题If x-9 = 2y and x+3 = 5y, what is the value of x?A-2B4C11D15E17
单选题
If x-9 = 2y and x+3 = 5y, what is the value of x?
A
-2
B
4
C
11
D
15
E
17
参考解析
解析:
Subtract corresponding sides of the two given equations: x+3=5y, x- 9= 2y →0+ 12=3y. 12/3 = y or y=4. Since y= 4 and x + 3 = 5y, then x + 3 = 5(4) = 20, so x=20-3=17.
Subtract corresponding sides of the two given equations: x+3=5y, x- 9= 2y →0+ 12=3y. 12/3 = y or y=4. Since y= 4 and x + 3 = 5y, then x + 3 = 5(4) = 20, so x=20-3=17.
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