$-1.2x=2(x+2.15)\\Simplifying\\-1.2x=2x+4.3\\Subtracting\ 2x\ from\ both\ sides\\-1.2x-2x=2x+4.3-2x\\-3.2x=4.3\\Dividing\ both\ sides\ by\ -3.2\\\frac{-3.2x}{-3.2}=\frac{4.3}{-3.2}\\x=-1.34375\\Rounding\ off\ to\ nearest\ 100th\\x=-1.34$

Hence, option D: x=-1.34 is correct

Keywords: Linear equation in one variable, Solution of equation

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5 0

3 years ago

HELp I will give brainliest!!

3241004551 [841]

Answer:

$c=\sqrt{65}=8.062.$

Step-by-step explanation:

$\text{Consider } \bigtriangleup DBC, \text{by Pythagoras}\\DB^2+BC^2=DC^2 \\\Rightarrow b^2=DC^2-BC^2\\\Rightarrow b^2= 5^2-3^2=25-9\\\Rightarrow b^2= 16\\\text{Then } , b=4.\\ \text{Consider } \bigtriangleup DBA, \text{by Pythagoras}\\DB^2+BA^2=DA^2\\\Rightarrow c^2=b^2+BA^2\\\Rightarrow c^2=4^2+7^2\\\Rightarrow c^2=16+49\\\Rightarrow c^2=65\\\text{Then } , c=\sqrt{65}=8.062.$

7 0

2 years ago