中一數學~~~~

x = john's savins
y = john's sister's savins

x - 300 = y
x - 450 = (2/5) (y+450)


x = (2/5) (x-300+450) +450
5x = 2(x+150) + 2250
5x - 2x = 300 + 2250
3x = 2550
x = 850

Total savings = x + y = 850 + (850-300) = 1400

Do you mean (2a + 3) / 4 - (a + 4) / 3 = a + 1 ?

3(2a+3) - 4(a+4) = 12(a+1)
6a + 9 -4a -16 = 12a + 12
2a -7 = 12a + 12
-7 - 12 = 12a - 2a
-19 = 10a
a = -19/10 = -1.9

for no.1 since so many people ans the que. so i don't ans la !!!!!!!!!!!!!!!

no.2
if your que is not wrong, than....

2a+3/4-a+4/3=a+1 (the whole equation times 12)
24a+9-12a+16=12a+12
12a+25=12a+12

than this que has no ans. Because how can ...........
12+25=12+12 ( just let a=1)
37=24

????????? 37=24 ??????????
immpossible!!!!!!!!!


hope i can you la ( ^ U ^ )
i also hope that you can choose as the best ans la ( > 3 < )

let john's savins is X
john's sister's is Y

X =Y +300.....................1
X - 450 = (2/5) (Y+450)..............2

Sub 1 into 2
Y - 150 = (2/5)(Y+450)
Y - 150 = 2/5Y + 180
5Y= 2Y + 1650
3Y= 1650
Y= 550
Sub Y=550 into 1
X = 850
Altogether they have save 550+850= $1400



(2a+3)/4 - (4-a+4)/3 = a+1
3(2a+3) - 4(4-a+4) = 12a +12
6a+9 - 4a - 16 = 12a + 12
10a = - 19
a = -1.9

Let John sister's saving be X,

Then John's saving =X+300

(X+300)-450= (X+450) * 2/5
X-150= (2X+900)/5
5X-750 = 2X+900
3X = 1650
X= 550

John's Sister has $550 and John has $850


For ２ａ＋３／４－ａ＋４／３＝ａ＋１ , could you please confirm the question again? is there any blanket?

Let x and y be John's savies and his sister's savies resp.
x - y = 300-------------------------------(1)
x - 450 = (y + 450)2/5---------------(2)
From (1),
y = x - 300------------------------------(3)
Sub (3) into (2)
x - 450 = [(x - 300) + 450]2/5
x - 450 = (x + 150)2/5
x - 450 = 2x/5 + 60
x - 510 = 2x/5
5x - 2550 = 2x
3x = 2550
x = 850
Sub x = 850 into (3)
y = 850 - 300
y = 550
∴They have altogether $(850 + 550) = $1400