Math
posted by anonymous on .
I need help solving this using the substitution method
4p2q= 16,
5p + 7q= 1

1975=

Start with one formula.
4p  2q = 16
Get one variable alone on one side of the equation.
2q = 16  4p
q = 2p  8
Then substitute the value into the other equation.
5p + 7q = 1
5p + 7(2p  8)= 1
Solve for p.
Once you find p, put that value into the first equation to solve for q. To check, put both values back into the second equation.
I hope this helps. Thanks for asking. 
4 p = 16 + 2 q
so
p = (4 + .5 q)
substitute that value for p in the second equation
5 (4 + .5 q) + 7 q = 1
20 + 2.5 q + 7 q = 1
9.5 q = 19
q = 190/95 = 38/19 =2
put that back in either first or second equation to solve for p
p = 4 + .5*(2)
p = 4  1 = 3
check
4(3) 2 (2) = 12 + 4 = 16 check
5(3) + 7(2) = 15  14 = 1 check