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# 4x+y=5 ;x+y=1 ?????

0
535
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4x+y=5 ;x+y=1 ?????      aking first-degree equations with two unknowns?

Guest Jun 10, 2015

#2
+14536
+10

#### x + y = 1      | Subtraction      =>     3x = 4   =>      x = $${\frac{{\mathtt{4}}}{{\mathtt{3}}}}$$         y  = 1 - 4/3 = $${\mathtt{\,-\,}}{\frac{{\mathtt{1}}}{{\mathtt{3}}}}$$

#1
+93691
+10

4x+y=5 (1)

x+y=1   (2)

(1)-(2)

3x=4

x=4/3

Sub into (2)

4/3 + y = 1

y=-1/3

Melody  Jun 10, 2015
#2
+14536
+10

#### x + y = 1      | Subtraction      =>     3x = 4   =>      x = $${\frac{{\mathtt{4}}}{{\mathtt{3}}}}$$         y  = 1 - 4/3 = $${\mathtt{\,-\,}}{\frac{{\mathtt{1}}}{{\mathtt{3}}}}$$

#3
+20033
+5

4x+y=5 ;x+y=1 ?????      aking first-degree equations with two unknowns ?

$$\small{\text{ \begin{array}{lccrcl} (1)&:& & 4x + y &=& 5 \\ (2)&:& & x + y &=& 1 \\ \hline &\\ (1) - (2)&:& & 4x - x + y - y &=& 5-1\\ & & & 3x &=& 4 \qquad |\qquad : 3\\ & & & {x} &{=}& { \frac{4}{3} }\\ \hline &\\ (2)&:& & x + y &=& 1 \\ & & & \frac{4}{3} +y &=& 1 \qquad |\qquad -\frac{4}{3}\\ & & & y &=& 1 -\frac{4}{3} \\ & & & {y} &{=}& {-\frac{1}{3}} \\ \end{array} }}$$

heureka  Jun 10, 2015