Question

Find the solution to x = 3y – 8 and 4x + 5y = 19 by the substitution method.
Would anyone mind giving me step by step instructions?

Answer 1

x= 3y- 8- (1)
4x+ 5y= 19- (2)
sub (1) into (2)
4(3y-8)+5y= 19
12y-32+5y= 19
17y-32= 19
17y= 51
y= 3
sub y=3 into (1)
x= 3(3)-8= 1
therefore x=1, y=3

Answer 2

Thank you so much! @jocelynong would you mind answering one more question for me?

Answer 3

if i can, ill try

Answer 4

@jocelynong
Find the solution to 4x + y = 10 and 3x – y = 39 by the elimination method.

Answer 5

it put question marks for some reason. it's 3x-y=39

Answer 6

4x+y= 10- (1)
3x- y= 39 - (2)
(2)+ (1): 3x-y+(4x+y)= 39+10
7x= 49
x= 7
so sub x= 7 in (1)
4(7)+ y= 10
y= -18
therefore x=7, y= -18

Answer 7

thank youuuu! this means a lot to me :) @jocelynong

Answer 8

hahah welcome. you don't happen to know differentiation do you? hehe