Answer: The number is: "2 " . __________________________________________ Explanation: __________________________________________ Write the expression; which is an equation, as follows: __________________________________________ " 4x <span>− 12 = 2(-x) " ; in which "x" represents "the number for which we shall solve" . ___________________________________________ Note:
If the "number" = "x" ; the "opposite of the number" = " -x " ; </span>___________________________________________ Rewrite as: " 4x <span>− 12 = -2x " ; </span>_____________________________________________ → Add "12" ; & add "2x" ; to EACH SIDE of the equation:
4x − 12 + 12 + 2x = -2x + 12 + 2x ;
to get: 6x = 12 ; ____________________________________________________ Now, divide each side of the equation by "6" ; to isolate "x" on one side of the equation; & to solve for "x" ; ____________________________________________________ 6x / 6 = 12 / 6 ;
to get: x = 2 . ____________________________________________________ Answer: The number is: "2 " . ____________________________________________________ Let us check our answer, by plugging in "2" for "x" in our original equation: _____________________________________________________ → " 4x − 12 = 2(-x) " ;
Let us plug in "2" for "x" ; to see if the equation holds true; that is; if both side of the equation are equal; when "x = 2" ;
Step 1. Calculate the volume of gasoline tank (V) using the known mass (m) and density of gasoline (D). D = m/V ⇒ V = m/D D = 719.7 kg/m³ m = 45.0 kg V = 45.0 kg/719.7 kg/m³ = 0.0625 m³
Step 2. Calculate the depth of the tank (d) using the known volume (V) of gasoline and width (w) and length (l) of the tank: V = d * w * l 0.0625 = d * 0.900 * 0.450 0.0625 = d * 0.405 d = 0.0625 / 0.405 d = 0.154 m
