F.2 linear equations ( MATHS)

Let x be the age of Bonnie and y be Clyde's
For their daughter is 19 years old,so they married at 19 years ago.
(x-19)/(y-19)=7/8
8x-152=7y-133
8x-7y=19.............(1)

For 16 years later,the sum of them will 100 years old.
(x+16)+(y+16)=100
x+y+32=100
x+y=68................(2)

Therefore,(1)+7(2)
8x-7y+7(x+y)=19+7(68)
8x-7y+7x+7y=19+476
15x=495
x=33....................(3)

Sub.(3) into (2)
(33)+y=68
y=35

So,Bonnies is 33 years old and Clyde is 35 years old.

Let x be the Bonnie's age and y be the Clyde's age

(x﹣4) = 7/8 (y﹣4) ------------- -- (1)
(x + 16) + (y + 16) = 100 ----------- (2)

from (1),
(x-4) = 7/8 (y-4)
8(x-4) = 7(y-4)
8x - 32 = 7y - 28
i.e. 8x = 7y + 4

from (2),
(x + 16) + (y + 16) = 100
x + y + 32 = 100
x = 68﹣y -----------------(3)

Substitute (3) into (1)
8(68 - y) = 7y + 4
544﹣8y = 7y + 4
15y = 540
y = 36

Substitute y = 16 into (3)
x = 68﹣36
x = 32

Therefore, Bonnie and Clyde are 32 and 36 years old now respectively.