Question

Va roooooooooooooog frumos

Answer 1

a) Se foloseste formula $(a+b)^{2}= a^{2}+2*a*b+ b^{2} \\ (4*x) ^{2}-2*4*x*3+9-9( x^{2} +3*x-10)=7( x^{2}+4*x+4)-8 \\ 16* x^{2} -24*x+9-9* x^{2} -27*x+90=7* x^{2} +28*x+20$
Se reduc termenii in [tex] x^{2} [/tex]
-24*x+9-27*x+90=28*x+20
-51*x-28*x=20-90-9⇒-79*x=-79 deci x=1
b)-4x+$x^{2}$-(4x+2$x^{2}$+2+x)+(9+6x+$x^{2}$)=4x-$x^{2}$-4+x-x+$x^{2}$+1
In membrul drept se reduc termenii in $x^{2}$ si rezulta
4-4x+$x^{2}$-4x-2$x^{2}$-2-x+9+6x+$x^{2}$=4x-3
Dupa reducerea termenilor in $x^{2}$ si din membrul stang obtinem ecuatia -3x+11=4x-3⇒-7x=-14⇒x=2