Graphs

Miss Fotheringale teaches her maths class how to plot graphs. For the first exercise her pupils plot the line $y = ax + b$ with asterisks for every $x$ from 0 to 10.

Write a program that prints the correct graphs so she can mark the work quickly.

The first line contains $N$, the number of graphs to plot ($0 < N < 30$).

Each of the next $N$ lines describes one graph and holds two non-negative integers $A$ and $B$ separated by a space, the values of $a$ and $b$ ($0 \le A, B < 10$). $A$ and $B$ are never both 0.

For each graph, first print the equation on a line of its own. That line is y = , then the value of $A$, then x + , then the value of $B$, concatenated in that order.

Below it print the graph, a grid 11 columns wide and $A \times 10 + B + 1$ rows tall. The columns correspond to $x = 0, 1, \dots, 10$ from left to right. The bottom row is $y = 0$, each row above it raises $y$ by 1, and the top row is $y = A \times 10 + B$.

Print * in cell $(x, y)$ when $x = 0$ (the $y$ axis), when $y = 0$ (the $x$ axis), or when $y = Ax + B$. Print a space otherwise. Trailing spaces at the end of a line are ignored.