Question

Stiind ca ( x = 14 ) calculează a+b in fiecare caz :

[•]= Inmulțit

A) a+b-3x=56
B)11•a+11•b+56+x=1170
C)7•a+7•b+7•x=700
D)30•x-a-b=241
E)39•a+39•b-39•x=3900
F)9•x-2a-2•b=100
G)x•a+x•b=140
H)x•a+x•b+6•a+6•b=200

Answer 1

a) a+b-3*14=56 => a+b = 56-42 = 14

b) 7*a+7*b+7*14=700 => 7(a+b) = 602 => a+b = 86

c) 39*a+39*b-39*14=3900 => 39(a+b) = 3354 => a+b = 86

d) 14*a+14*b=140 => 14(a+b) = 140 => a+b = 10

e) 11*a+11*b+56+14=1170 => 11(a+b) = 1100 => a+b = 100

f) 30*14-a-b=241 <=> 420-(a+b)=241 = a+b = 179

g) 9*14-2*a-2*b=100 <=> 126- 2(a-b)=100 => 2(a-b) = 26 => a-b = 13

h) 14*a+14*b+6*a+6*b=200 <=> 14(a+b) + 6(a+b) = 200 <=> (a+b)(14+6)=200 => a+b=10

Answer 2

a) = a+b- 3×14= 56

=a+b-42= 56

= a+b= 56+42= 98

B)= 11×a+11×b+56+14= 1170

= 11×(a+b) + 70 = 1170

= 11×(a+b)= 1170-70= 1100

a+b= 1100÷11= 100

C)= 7a+7b+7x= 700

= 7×(a+b+14) = 700

a+b+14= 700÷7= 100

a+b= 100-14= 86

D)= 30x -(a+b)= 241

   = 30×14−(a+b)= 241

= 420 − (a+b) = 241

=a+b= 420−241 =179

E) = 39(a+b+14)= 3900

= a+b+14 = 100

a+b= 100-14= 86

F)=9×14−(2a+2b) = 100

= 126−(2a+2b)= 100

= 2a+2b= 126 -100 = 26

= 2×(a+b) = 26

a+b= 26÷2= 13

G)= 14a+14b=140

=14×(a+b) = 140

= a+b= 140÷14= 10

a+b= 10

H)= 14a+14b+6a+6b=200

=20a+20b= 200

=20×(a+b)= 200

=a+b= 200÷20= 10

=a+b= 10