7+14+15+5+8 + 9 =58 yard
answer 58 yd
Part a: the first cereal is y=7x and the second one is y=10x so they are $3 apart.
part b: y=7*4 (28) and y=10*4 (40) is $12 apart so she will save $12 each month.
Can you take the quantity [ x + y ] and square it ?
Can you take the quantity [ x + 2y ] and square it ?
Then you should have no trouble with the square of (.9x + .8y) .
The square of any binomial (expression with 2 terms) is
(square of the first term)
+ (square of the second term)
+ 2 times (product of the terms) .
