Question

solve 5x-4y=-1 , 2x-y=-1 by subtution method​

Answer 1

Step-by-step explanation:

x=-1 + 4y/5.....(1)

2x-y=-1

put the value of eq 1

2(-1+4y/5) -y= -1

now, (-2 + 8y)/5 -y = -1

-2+8y-5y=-5

3y=-3

so, y=-1..... (2)

now, put eq 2 in eq 1

x=-1 -4/5

x= -5/5

x=-1

Answer 2

❋Question:

Solve 5x-4y=-1 , 2x-y=-1 by subtitution method....?

❋Answer:

☛We have given system of equations:

↬5x - 4y = -1.....equation (1)

↬2x - y = -1.....equation (2)

♟By usìng Substitution method,

☛From eqn.(2)

$⇢ \large{ \sf{2x = y - 1 }} \\ \\⇢ \large{ \sf</strong><strong>{</strong><strong>\</strong><strong>boxed</strong><strong>{</strong><strong>\</strong><strong>pink</strong><strong>{x = \frac{y - 1}{2} </strong><strong>}</strong><strong>}</strong><strong>}}$

☛Substituting x= y-1/2 in eqn(1),

$⇢ \large{ \sf{5( \frac{y - 1}{2} ) - 4y = - 1}} \\ \\ ⇢ \large{ \sf{ \frac{5(y - 1) - 8y}{2} = - 1}} \\ \\ ⇢ \large{ \sf{ \frac{5y - 5 - 8y}{2} = - 1}} \\ \\ ⇢ \large{ \sf{ \frac{ - 3y - 5}{2} = - 1}} \\ \sf{ \underline{ \underline{ \dag{ \green{ \: cross \: multiplying...}}}}} \\ \\ ⇢ \large{ \sf{ - 3y - 5 = - 2}} \\ \\ ⇢ \large{ \sf{ - 3y = 3 \: \: \: \: \: \: \: \: \: \: \: \: ( 5 + ( - 2) = 3)}} \\ \\ ⇢ \large{ \sf{y = \cancel{\frac{ - 3}{3} }}} \\ \\ ⇢ \large{ \sf{ \boxed{ \purple{y = - 1}}}}$

☛ Putting value of y in expression of x

$⇢ \large{ \sf{x = \frac{ - 1 - 1}{2} }} \\ \\ ⇢ \large{ \sf{x = \cancel{\frac{ - 2}{2} }}} \\ \\ ⇢ \large{ \sf{ \boxed{ \purple{x = - 1}}}}$

❋Hence, The final answer:

$\huge{ \boxed{ \bold{ \red{x = - 1 \: and \: y = - 1}}}}$