Answer:
1) x=-0.5 and x=-3.41
2) 12x^2
Step-by-step explanation:
a) 7-x^2=4x-5
7-x^2-4x+5=0
-x^2-4x-2=0
Multiply by -1
x^2+4x+2=0
Solve using quadratic formula [tex]$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$[/tex]
we have a=1, b=4, c=2
Putting values to find x
[tex]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\x=\frac{-(4)\pm\sqrt{(4)^2-4(1)(2)}}{2(1)}\\x=\frac{-4\pm\sqrt{16-8}}{2}\\x=\frac{-4\pm\sqrt{8}}{2}\\x=\frac{-4+\sqrt{8}}{2} \ and \ x=\frac{-4-\sqrt{8}}{2}\\x=-0.5 \ and \ x=-3.41[/tex]
So, x=-0.5 and x=-3.41
b) Simplify
[tex]3x(x+6)-3x(6-3x)[/tex]
[tex]3x(x+6)-3x(6-3x)\\=3x^2+18x-18x+9x^2\\=3x^2+9x^2\\=12x^2[/tex]
