x*x*4-9=142

Solution for x*x*4-9=142 equation:

x*x*4-9=142

We move all terms to the left:

x*x*4-9-(142)=0

We add all the numbers together, and all the variables

x*x*4-151=0

Wy multiply elements

4x^2*4-151=0

Wy multiply elements

16x^2-151=0

a = 16; b = 0; c = -151;
Δ = b2-4ac
Δ = 02-4·16·(-151)
Δ = 9664
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{9664}=\sqrt{64*151}=\sqrt{64}*\sqrt{151}=8\sqrt{151}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{151}}{2*16}=\frac{0-8\sqrt{151}}{32}
=-\frac{8\sqrt{151}}{32}
=-\frac{\sqrt{151}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{151}}{2*16}=\frac{0+8\sqrt{151}}{32}
=\frac{8\sqrt{151}}{32}
=\frac{\sqrt{151}}{4}
$