Answer:
c and e
Explanation:
(a)
x² - 4x + 3 = 0 ← is a quadratic and not linear
(b)
6x - 2y = 7 ← is a linear equation in 2 variables, x and y
(c)
3x - 1 = - 2x ( add 2x to both sides )
5x - 1 = 0 ← is a linear equation in 1 variable
(d)
pq - 3 = p ← is a linear equation in 2 variables , p and q
(e)
3x + 2 = 4(x + 7) + 9 ← is a linear equation in 1 variable