math
posted by jaton on .
using the substitution method what is the answer to this problem, x+3y=7 x+4y=12

x + 3 y = 7 Subtract 3 y to both sides
x + 3 y  3 y = 7  3 y
x = 7  3 y
Put x = 7  3 y into equation x + 4 y = 12
7  3 y + 4 y = 12
7 + y = 12 Subtract 7 to both sides
7 + y  7 = 12  7
y = 5
Replacing y = 5 into x = 7  3 y gives
x = 7  3 * 5
x = 7  15
x =  8