Odpowiedź:
a. 3x-19=3•9-19=27-19=8
b. x^2+9x-4=(6)^2+9•6-4=36+54-4=86
c. 7x-9y=7•(-10)-9•7=-70-63=-133
d. 2a^2-7b=2•(7)^2-7•(-3)=98+21=119
e. 3x(2y-10)=3•(-4)(2•10-10)=-12•10=-120
f. (5x-y)-(4x+3y)=(5•(-2)-(-5))-(4•(-2)+3•(-5))=
=(-10+5)-(-8-15)=-5+23=18
a) x=9
3x-19= 3*9 -19= 27-19= 8
b) x=6
x² +9x -4= 6²+ 9*6-4= 36 + 54 -4= 90-4= 86
c) x= (-10) ; y= 7
7x -9y= 7*(-10) - 9*7= - 70 - 63= - 133
d) a=7 ; b= (-3)
2a²-7b= 2*7²- 7*(-3)= 2*49 +21= 98+21= 119
e) x= (-4) ; y= 10
3x( 2y -10)= 3*(-4) ( 2*10 -10)= -12 *20-10= -240 +120 = - 120
f) x= (-2) ; y= (-5)
(5x-y) - ( 4x+3y)= 5*(-2) - (-5) - 4*(-2) + 3* (-5)= -10 +5 +8 -15= -25+13= - 12
Szczegółowe wyjaśnienie:
