Question

1) 7y+5y-8,para y=3
2)6*(x-2)+5-3x, para x=8
3)4*(a+2b)-15, para a= -6 e b=5
4)6x-12y+3*(6y+3),para x=2 e y =1/2
5)3*(14-5x)-(38a:2), para x= -2 e a=1
6)(7z-3)*4-(-9z):(-3),para z= -3

Answer 1

1) $7y+5y-8= \\ =7(3)+5(3)-8= \\ =21+15-8= \\ =36-8= \\ =28$
2) $6.(x-2)+5-3x= \\ =6.(8-2)+5-3(8)= \\ =6.(6)+5-24= \\ =36-19= \\ =17$
3) $4.(a+2b)-15= \\= 4.(-6+10)-15= \\ =4.(4)-15= \\ =16-15 =\\ =1$
4) $6x-12y+3.(6y+3)= \\ =6(2)-12( \frac{1}{2} )+3(6. \frac{1}{2}+3 )= \\ =12- \frac{12}{2} +3( \frac{6}{2}+3 )= \\ =12-6+3(6)= \\ =6+18= \\ =24$
5) $3(14-5x)-(38a:2)= \\ =42-15x-38(1):2= \\ =42-15(-2)-38:2= \\ =42+30-19= \\ =72-19= \\ =53$
6) $(7z-3)4-(-9z):(-3)= \\ =28z-12-3z= \\ =28(-3)-12-3(-3)=\\ =-84-12+9= \\ =-96+9= \\ =-87$