plase come , easy

17(a)x-7

17(b)(x+x-7)*2=74

17(c)(x+x-7)*2=74
(2x-7)*2=74
2x-7=37
2x=44
x=22

(18)Let the money Peter has be x.
x+x+40+x+40+210=860
3x+290=860
3x=570
x=190
Peter has $190, Jack has $230 and Tom has $440.

(P.71)
The length of a rectangle is x cm.
17(a) The length is 7 cm longer than the width .Express the width in terms of x.
Width = (x - 7) cm.

17(b) The perimeter is 74 cm . Write down an equation in x.
Given Perimeter = 2 (length + width)
Thus, the equation is
2 [x + (x - 7)] = 74
2(2x - 7) = 74
Or 2x - 7 = 37

17(c) Solve the equation in (b) . Hence find the dimenisions of the rectangle.
Recall 2x -7 = 37
2x = 44
x = 22 cm. (Ans.)
x - 7 = 22 - 7 = 15 cm. (Ans.)
Ans. The length is 22 cm. and
The width is 15 cm.

18) Divide $860 between Tom , Jack and Peter , so ha Tom has $210 more then Jack , and Jack has $40 more than Peter .How much does each get.
Let $a be the amount Tom gets;
$b be the amount Jack gets;
$c be the amount Peter gets;
Thus, a = b + 210
b = c + 40
therefore, a = c + 40 + 210 = c + 250
Given a + b + c = 860
That is, (c + 250) + (c + 40) + c = 860
3c + 290 = 860
3c = 570
c = 190 (Ans.)
b = c + 40 = 190 + 40 = 230 (Ans.)
a = b + 210 = 230 + 210 = 440 (Ans.)
Ans. Tom gets $440; Jack gets $250; Peter gets $190.

19) A nad B are two consecutive numbers (B

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2007-08-13 11:45:37 補充：
19) A nad B are two consecutive numbers (B B = A 1......

2007-08-13 15:14:43 補充：
19) A nad B are two consecutive numbers (B A = B 1 (ascending) orA = B - 1 (decending)........