Question

Find $x,y$ if $-4x+y=4$ and $2x+\frac{7}{8}y=\frac{3}{4}$

• A. $\frac{1}{2},2$
• B. $1,-\frac{3}{2}$
• C. $-1,\frac{5}{2}$
• D. $-1,4$

Answer 1

The correct option is A $\frac{1}{2},2$

Given
$-4x+y=4$.....eq(1)
$2x+\frac{7}{8}y=\frac{3}{4}$....eq(2)....multiplied by 2
on adding both we get
$-4x+y=4$\quad
$4x+\frac{14}{8}y=\frac{6}{4}$
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$y+\frac{14y}{8}=4+\frac{6}{4}$
$\Rightarrow \frac{8y+14y}{8}=\frac{16+6}{4}$
$\Rightarrow \frac{22y}{8}=\frac{22}{4}$
$\Rightarrow 4y=8$
$\Rightarrow y=2$
putting the value of y=2 in eq (1)
$-4x+y=4$
$-4x=4-2$
$-4x=2$
$x=\frac{1}{2}$
$x=1/2$ and $y=2$