It is known that f (x) = x ^ 3 + ax ^ 2 + BX + 3, and the tangent equation of curve y = f (x) at point (1, F1)) is 5x + Y-3 = 0 Finding the value of a and B

It is known that f (x) = x ^ 3 + ax ^ 2 + BX + 3, and the tangent equation of curve y = f (x) at point (1, F1)) is 5x + Y-3 = 0 Finding the value of a and B

f'(x)=3x^2+2ax+b
F (1) = a + B + 4, which is substituted into tangent equation: 5 * 1 + A + B + 4-3 = 0, that is, a + B = - 6
The tangent slope is f '(1) = - 5 = 3 + 2A + B, that is, 2A + B = - 8
A = - 2, B = - 4