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There is something missing in "... half the sum of [???] and y decreased ...".
(x + y)/2 ------------
1/2 (x+y)
Twice the sum of 'x' and 'y' . . . 2(x+y) The sum of twice 'x' and 'y' . . . (2x+y)
The expression is: 2y -20
2(x+y)=2x+2y
The sum of x and y decreased by their product is (x + y)- xy.
5(x^2 + y)
6x - (6 + y)
(x + y)/2 ------------
1/2 (x+y)
Twice the sum of 'x' and 'y' . . . 2(x+y) The sum of twice 'x' and 'y' . . . (2x+y)
y-8
2(x+y) is twice the sum of x and y, and 2x+y is the sum of twice x and y
y-6
17 - y
To find 4 times the sum of y and 7, you first calculate the sum of y and 7, which is y + 7. Then, you multiply this sum by 4 to get the final result. Therefore, the expression for 4 times the sum of y and 7 is 4(y + 7), which simplifies to 4y + 28.
8 + y