Answer:
B)-4
Step-by-step explanation:
y=mx+c
sub in a point and gradient/slope to get c
-7=3(-1)+c
-7=-3+c
-7+3=c
c=-4
y=3x-4
if u looking for the y intercept make x=0
y=3(0)-4
y=-4
Answer: 7
Step-by-step explanation: Cross multiply, so 15 times x and 21 times 5. 21 times 5 is 105 then you divide by 15 which gives you 7.
Answer:
The correct answer for the second one is,

Answer:
D
Step-by-step explanation:
the answer is D: Both 3 and 4