2.2 Leikkauspisteitä

237

b)
$3^3+3^3=3^3\cdot a$
$54=27a$
$a=2$

228

b)
$\left|3-2x\right|=5$
$3-2x=5$
$-2x=2$
$x=-1$
$3-2x=-5$
$-2x=-8$
$x=4$

224

$y=1$
$x^2+y^3-3y^2+3y=5$
$x^2+1^3-3\cdot1^2+3=5$
$x^2+1=5$
$x^2=4$
$x=\pm2$

223

(1, 2), (1, 0), (1, -2)
$y^3=x+4y-1$
$\left(1{,}\ 2\right)$
$2^3=1+4\cdot2-1$
$8=1+8-1$
$\left(1{,}\ 0\right)$
$0=1-1$
$\left(1{,}\ -2\right)$
$-8=1-8-1$
$-8=-8$

221

(-3, 0), (0, 1) ja (0, -3)

$\left(-3{,}\ 0\right)$
$y^2-x+2y-3=0$
$0-\left(-3\right)+2\cdot0-3=0$
$0+3+0-3=0$
$3-3=0$
$0=0$
$\left(0{,}\ 1\right)$
$1-0+2-3=0$
$3-3=0$
$0=0$
$\left(0{,}\ -3\right)$
$9-0+2\left(-3\right)-3=0$
$9-6-3=0$
$0=0$

222

a)
$4x^2+xy+y^2=9$
$4x^2+0x+0^2=9$
$4x^2=9$
$2x=\pm3$
$x=\pm\frac{3}{2}$
b)
$4x^2+xy+y^2=9$
$y^2=9$
$y=\pm3$
c)