Question

CAN anyone help me with this question?

Answer 1

`4 [cm]`

Explanation:

`A` - area

`x` - base

`h` - height

·
`A=(1)/(2) xh\\h=x+3[cm]\\A=14[cm^(2) ]\\\\\\(1)/(2) x(x+3)=14\\x(x+3)=28\\x^(2) +3x-28=0`

Quadratic equation coefficients:

`a=1 \\b=3 \\c=-28\\\Delta=b^2 - 4ac\\\Delta=9-4(-28)\\\Delta=121\\√(\Delta) =11\\x_1 =(-b-√(\Delta))/(2a) \\x_1 = (-3-11)/(2) \\x_1 = -7 < 0\\\\x_2 =(-b+√(\Delta))/(2a) \\x_2 = (-3+11)/(2) \\x_2 = 4 [cm]`