Question

N 14) Determinați valoarea lui x din figura 3. D 4x + 250° B 2x+10° 3x - 10° C 3x + 4° B​

Answer 1

Răspuns:

)3(2x−3)=4(3x+5)

3×2x−3×3=4×3x+4×5

6x−9=12x+20

6x−12x=20+9

−6x=29

x=

6

−29

\begin{gathered}b)5(3x + 5) = 7(3x - 10) \\ 5 \times 3x + 5 \times 5 = 7 \times 3x - 7 \times 10 \\ 15x + 25 = 21x - 70 \\ 15x - 21x = - 25 - 70 \\ - 6x = - 95 \\ x = \frac{ - 95}{ - 6} \\ x = \frac{95}{6} \end{gathered}

b)5(3x+5)=7(3x−10)

5×3x+5×5=7×3x−7×10

15x+25=21x−70

15x−21x=−25−70

−6x=−95

x=

−6

−95

x=

6

95

\begin{gathered}c) 10(2x - 5) = 5(2x - 9) \\ 10 \times 2x - 10 \times 5 = 5 \times 2x - 5 \times 9 \\ 20x - 50 = 10x - 45 \\ 20x - 10x = 50 - 45 \\ 10x = 9 \\ x = \frac{9}{10} \end{gathered}

c)10(2x−5)=5(2x−9)

10×2x−10×5=5×2x−5×9

20x−50=10x−45

20x−10x=50−45

10x=9

x=

10

9

\begin{gathered}d)5(3x - 8) = 4(4x + 7) \\ 5 \times 3x - 5 \times 8 = 4 \times 4x + 4 \times 7 \\ 15x - 40 = 16x + 28 \\ 15x - 16x = 40 + 28 \\ - x = 68 \: \: \: | \times ( - 1) \\ x = - 68\end{gathered}

d)5(3x−8)=4(4x+7)

5×3x−5×8=4×4x+4×7

15x−40=16x+28

15x−16x=40+28

−x=68∣×(−1)

x=−68