3. Which equation is not true?
A. \( -7.56 \div 2.4-0.65=-3.8 \)
B. \( \left(5 \frac{1}{8}-\frac{3}{4}\right) \div\left(-1 \frac{3}{4}\right)=-2.5 \)
C. \( -\frac{5}{8}\left(\frac{8}{3}+1 \frac{1}{3}\right)=-2.2 \)
D. \( -8.2+6.5 \cdot(-3.4)=-30.3 \)
Answer
4. \( -8.2+6.5 \cdot(-3.4) = -8.2 - 22.1 = -30.3 \)
Step 1 ：1. \( -7.56 \div 2.4-0.65=-3.8 \Rightarrow (-7.56 \div 2.4) - 0.65 = -3.15-0.65= -3.8 \)
Step 2 ：2. \( \left(5 \frac{1}{8}-\frac{3}{4}\right) \div\left(-1 \frac{3}{4}\right) = \left(\frac{41}{8}-\frac{3}{4}\right) \div -\frac{7}{4} = \frac{35}{8} \div -\frac{7}{4} = -2.5 \)
Step 3 ：3. \( -\frac{5}{8}\left(\frac{8}{3}+1 \frac{1}{3}\right) = -\frac{5}{8} \left(\frac{8}{3}+\frac{4}{3}\right) = -\frac{5}{8} \cdot \frac{12}{3} = -\frac{5}{2} \neq -2.2 \)
Step 4 ：4. \( -8.2+6.5 \cdot(-3.4) = -8.2 - 22.1 = -30.3 \)
