Answer:
In 7 years, the savings account will have earned $210 in interest.
Explanation:
To solve for how much interest(y) there will be after 7 years(x), you just need to plug it into the equation:
y = 30x, where x is 7
y = 30(7)
y = 210
So the interest earned in 7 years is $210.
(Also, if you need to graph the situation, just plot a point that fits in the equation, like (7, 210), and draw a line through it that also passes through the origin, because the origin is the y-intercept)