Question

substitute for y=4x-1;y=2x-5

Answer 1

you can say 2x - 5 = 4x - 1 ⇒ 2x - 4x = 5 - 1 ⇒ -2 x = 4 ⇒ x= -2 and y gonna be 
y = -4 -5 = -9 :D

Answer 2

y=4x−1;y=2x−5
Step: Solve y=4x−1 for y:
Step: Substitute 4x−1 for y in y=2x−5:
y=2x−5
4x−1=2x−5
4x−1+−2x=2x−5+−2x(Add -2x to both sides)
2x−1=−5
2x−1+1=−5+1(Add 1 to both sides)
2x=−4
2x/2=−4/2(Divide both sides by 2)
x=−2
Step: Substitute−2 for x in y=4x−1:
y=4x−1
y=(4)(−2)−1
y=−9(Simplify both sides of the equation)
Answer:y=−9 and x=−2