2x7=14double = 4x7= 28
28
4x7=28 2(4x7)=2x28=56
32
4x7=28(4x7=2x28=56
-6x3 + 4x7 - 0.8x2 + x4 - 5x5 = 4x7 - 5x5 + x4 - 6x3 - 0.8x2 = x2 (4x5 - 5x3 + x2 - 6x - 0.8)
You can use the product from 4x7 to find the product of 8x7 by doubling the answer to 4x7. The product of 4x7 is 28 and the product of 8x7 is 56 (28 doubled is also 56).
the answer for 4x76 is 304
50
Double it.
28
4x7=34