if 3x +4y =7 and 10x-y=9,then find the value of 2x+3y.
Answers
Answered by
10
Step-by-step explanation:
3x+4y=7-----------(1)
10x-y=9-------------(2)
(1)×10=30x+40y=70
(2)×3 =30x -3y=27
(-) (+) (-)
-------------------------------
43y=43
y =1
putting the value of y in equation (1) we can get
3x+4y=7
=>3x+4×1=7
=> 3x+4=7
=>3x=3
=> x=1
2x+3y=2×1+3×1=2+3=5
Answered by
5
Answer:
Given equation is 3x+4y=7
If x=1 put in equation we get
(i)3×1+4y=7
⇒3+4y=7
⇒4y=7−3
⇒4y=4
⇒y=1
(1,1)
If x=2 put in equation we get
(i)3×2+4y=7
⇒6+4y=7
⇒4y=7−6
⇒4y=1
⇒y=
4
1
(2,
4
1
)
If x=3 put in equation we get
(iii)3×3+4y=7
⇒9+4y=7
⇒4y=7−9
⇒4y=−2
⇒y=−
4
2
(3,−
4
2
)
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