If (a,4) is a point on the graph of y=x^2+3x what is a

Answer 1

If the point (a, 4) is on the graph of y = x² + 3x, that means when x = a, y=4. So, substitute and solve for "a".

4 = a² + 3a

a² + 3a - 4 = 0

(a + 4) (a - 1) = 0

a = -4 or a = 1

Check:

When a (or x) = 1

4 =? 1² + 3(1)

When a (or x) = -4

4 =? (-4)² + 3(-4) = 16 - 12 =4