Question

solve the following smultaneous equations
3x plus 2y =21 and x plus y = 8
3x -14y =0 and x - 4y plus 1 =0

Answer 1

for the 1st pair, since you know what y is , just plug that value into the first equation and solve for x

#2:

3x - 14y = 0
x - 4y + 1 = 0

3x - 14y = 0
multiply the 2nd by 3
3x - 12y = -3
subtract them
-2y = 3
y = -3/2
sub into x - 4y = -1
x - 4(-3/2) = -1
x + 6 = -1
x = -7

x = -7, y = -3/2